1 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Virtual Desktop Infrastructure with
Dell Fluid Cache for SAN This Dell technical white paper describes the tasks to deploy a high IOPS (heavy user) 800-user virtual desktop environment in a VMware Horizon View VDI infrastructure by leveraging Fluid Cache and Compellent storage array
A Dell Reference Architecture
January 2015
2 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Revisions
Date Description
January 2015 Initial release
THIS WHITE PAPER IS FOR INFORMATIONAL PURPOSES ONLY AND MAY CONTAIN TYPOGRAPHICAL ERRORS AND
TECHNICAL INACCURACIES THE CONTENT IS PROVIDED AS IS WITHOUT EXPRESS OR IMPLIED WARRANTIES OF
ANY KIND
copy 2015 Dell Inc All rights reserved Reproduction of this material in any manner whatsoever without the express
written permission of Dell Inc is strictly forbidden For more information contact Dell
PRODUCT WARRANTIES APPLICABLE TO THE DELL PRODUCTS DESCRIBED IN THIS DOCUMENT MAY BE FOUND
AT httpwwwdellcomlearnusen19terms-of-sale-commercial-and-public-sector Performance of network
reference architectures discussed in this document may vary with differing deployment conditions network loads and
the like Third party products may be included in reference architectures for the convenience of the reader Inclusion
of such third party products does not necessarily constitute Dellrsquos recommendation of those products Please consult
your Dell representative for additional information
Trademarks used in this text
Delltrade the Dell logo Dell Boomitrade Dell Precisiontrade OptiPlextrade Latitudetrade PowerEdgetrade PowerVaulttrade
PowerConnecttrade OpenManagetrade EqualLogictrade Compellenttrade KACEtrade FlexAddresstrade Force10trade and Vostrotrade are
trademarks of Dell Inc Other Dell trademarks may be used in this document Cisco Nexusreg Cisco MDSreg
Cisco NX-
0Sreg
and other Cisco Catalystreg
are registered trademarks of Cisco System Inc EMC VNXreg
and EMC Unispherereg
are
registered trademarks of EMC Corporation Intelreg
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and Celeronreg
are registered trademarks of
Intel Corporation in the US and other countries AMDreg
is a registered trademark and AMD Opterontrade AMD
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Windowsreg
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Internet Explorerreg
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and Active Directoryreg
are either trademarks or registered
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and Red Hatreg
Enterprise
Linuxreg
are registered trademarks of Red Hat Inc in the United States andor other countries Novellreg
and SUSEreg
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and XenMotionreg
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3 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Contents Revisions 2
Executive summary 5
1 Introduction 6
11 Objectives 6
111 Audience 6
2 Dell Fluid Cache for SAN and VDI 7
3 Solution architecture 9
31 Software Horizon view 9
311 Horizon view components 10
312 Virtual desktops 10
313 Horizon view desktop pools 11
314 Using linked clones 11
315 Hypervisor platform VMware vSphere 55 11
32 Hardware Dell infrastructure 12
4 Solution configuration 14
41 Host design considerations 14
42 Network design considerations 15
43 Dell Compellent SC8000 storage array configurations 16
44 vSphere host network configuration 17
45 Horizon view configuration 17
46 Windows 7 VM configuration 18
5 Horizon view test methodology 19
51 Test objectives 19
52 Test tools 19
521 Load generation 19
522 Monitoring tools 20
53 Test criteria 20
531 Storage capacity and IO latency 20
532 System utilization at the hypervisor 20
533 Virtual desktop user experience 21
534 Test configuration 21
4 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
6 Test results and analysis 22
61 Test scenarios 22
62 Boot storm IO 23
63 Login storm and steady state for standard users (LoginVSI Medium) 24
631 Server host performance 26
632 Monitoring user experience 29
633 Standard user test results summary 30
64 Login storm and steady state for heavy users (LoginVSI Medium + Iometer) 30
641 Server host performance 32
642 User experience monitoring 32
643 Heavy user test results summary 33
7 Best practices 34
71 Virtual Desktop Infrastructure 34
711 Implement roaming profiles and folder redirection 34
712 Boot and login storm considerations 34
713 Windows 7 master image for desktop VMs 34
714 VDI Management infrastructure recommendations 34
72 Server host 34
73 Network layer 35
74 Storage 35
8 Conclusion 36
A Horizon view solution configuration 37
B vSphere host network configuration 40
B1 vSwitch ndash Management traffic 40
B2 vSwitch - iSCSI 40
B3 vSwitch ndash Fluid Cache network 41
B4 vSwitch3 41
Additional resources 42
Acknowledgements 43
Feedback 43
5 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Executive summary
A Virtual Desktop Infrastructure (VDI) deployment can place high storage capacity and performance
demands on the storage platform For example consolidating large amounts of inexpensive stand-alone
desktop storage in to a centralized infrastructure can create tremendous storage capacity demands on
centrally managed shared storage used in VDI deployments Performance demands are determined by
the number of IO operations per second (IOPS) generated by basic desktop client operations such as
system boot logon and logoff and by desktop usage operations from different users Storm events such
as simultaneous booting of many desktops morning logons and afternoon logoffs by many users at
approximately the same time and virus scan can cause IO requirement variances that place high
performance demands on the storage infrastructure
Current VDI solutions in the market can cost-effectively manage desktop virtualization use cases where
performance demands are not really demanding For example a task worker environment in a call center
can generate 5ndash10 IOPSVM or a knowledge worker environment in an office can generate 15ndash25
IOPSVM Typically hybrid arrays or all-flash arrays are deployed to accommodate performance needs in
these VDI environments
The next frontier for VDI to conquer is the high IOPS use cases such as a software developer organization
or an engineering CADCAM team In these use cases not only the capacity demands are large
(repositories for code or design in development) but also performance demands are extremely high
(often 50ndash80 IOPSVM)
Dell Fluid Cache for SAN mdashan innovative server-side readwrite caching solution for workload
acceleration can provide an innovative cost-effective solution for high IOPS type VDI environments
Even though these VDI environments need a lot of storage capacity the working set is typically relatively
small However this working set is very IO intensivemdashmore read operations (write operations) during
boot storms and more write-operations during steady state Fluid Cache software can provide extremely
high IOPS with minimal latency for these working set VDI data leveraging PCIe SSDs as readwrite cache
pool in the computational tier while a Dell Compellent SAN storage array can provide the performance
and large capacity needed for the shared storage This combination fits perfectly for high IOPS VDI
environment
This technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed in a VMware Horizon View VDI infrastructure leveraging Fluid Cache and Compellent storage
array The test infrastructure also included Dell Networking switches and Dell PowerEdge servers running
VMware vSphere 55 as the hypervisor In the test environment the solution infrastructure successfully
hosted 800 desktops with satisfactory performance results across all layers of the stack including the
user layer hypervisor layer and storage layer while delivering approximately 90 IOPSVM as a sustained
steady state load Fluid Cache performance ensured excellent end-user desktop application response
times as determined by the user-level experience monitoring software LoginVSIrsquos VSIMax Details are
provided for the storage IO characteristics about various VDI workload scenarios such as boot and login
storms along with performance characteristics throughout the VDI stack
6 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
1 Introduction Desktop virtualization platforms such as VMware Horizon View 60 (Horizon View) can provide
organizations with significant cost savings streamlined implementation and ease of desktop
management In order to achieve these VDI benefits and to ensure optimal user experience the end-to-
end infrastructure design and sizing considerations need to be addressed carefully While VDI workloads
for task and knowledge workers are correctly understood by using many cost-effective solutions that are
available the high IOPS 800-user VDI use cases are addressed less often because current solutions
typically do not meet the stringent performance- and capacity requirements of these use cases in an
economically sensible manner
The goal of this technical white paper is to present the results of a series of storage IO performance tests
and provide the optimal end-to-end infrastructure design for high IOPS 800-user type VDI environments
leveraging Dell Fluid Cache for SAN Dell Compellent SAN storage arrays Dell PowerEdge servers and Dell
Networking switches
11 Objectives The primary objectives of the tests conducted for this technical white paper are
Develop an optimal end-to-end infrastructure design for a Horizon View and vSphere-based
heavy user type VDI solution deployed by using the Fluid Cache Compellent storage PowerEdge
servers and Dell Networking switches
Determine the performance at every layer of the VDI solution stack under high IOPS workload For
example desktops generating 80ndash90 IOPSVM at steady state
Determine the performance impact of peak IO activity such as boot and login storms
The test infrastructure used for the tests included
VMware Horizon View 60
VMware vSphere 55 hypervisor
Dell PowerEdge R720 servers with Dell Express PCIe SSDs
Dell Networking S4810 switches
Dell Compellent SC8000 storage array
111 Audience This technical white paper is intended for solution architects storage network engineers system
administrators and IT managers who need to understand about designing properly sizing and deploying
Horizon View-based VDI solutions by using Dell infra design properly sizing and deploying Horizon View-
based VDI solutions by using Dell infrastructure It is expected that the reader has a working knowledge of
the Horizon View architecture vSphere system administration iSCSI SAN network design and Dell
Compellent SAN operation
7 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
2 Dell Fluid Cache for SAN and VDI Dell Fluid Cache for SAN utilizes direct-attached Dell PowerEdge Express Flash NVMe PCIe SSDs and
remote direct memory access (RDMA) networking capabilities to create a clustered caching pool for
improved storage workload performance Applications write directly to the cache pool the
acknowledgement is sent back to the application and in the background the IO is flushed to the external
storage array Data is copied in to the cache pool when it is accessed (read) by application and is available
from the cache pool for reread operations Also data that is written into the cache pool by the application
is then available for reread operations from the application A high-speed link to other cache nodes in the
Fluid Cache for SAN pool allows the data to remain highly available by replicating blocks of data even if a
single node in cache pool stops working Fluid Cache for SAN provides a single management interface and
provides other capabilities such as cache-aware snapshots and replication and compression
Figure 1 shows an example environment highlighting how Fluid Cache for SAN communicates between
server and storage Three nodes are required to run Dell Fluid Cache for SAN software Two of these three
nodes are required to have a minimum of one Dell PowerEdge Express Flash NVMe PCIe SSD each and
the network for private cache network is based on the low-latency RDMA protocol The RDMA network
handles the cache pool communication between the nodes Creation and management of the Fluid
Cache cluster are accomplished by using the Dell Compellent Enterprise Manager software through
automatic cache server discovery
Figure 1 Dell Fluid Cache for SAN communication
8 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Fluid Cache for SAN is an ideal solution for high IOPS type VDI environment with highly write-intensive
workloads because it provides extremely fast and low-latency server-side write back caching Because
writes are mirrored across high-speed network and later destaged to the SAN with significant write
coalescing this solution can sustain significantly higher IOPSVM than an external hybrid or all-flash array
ndashbased solution could
9 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
3 Solution architecture The overall architecture of the VDI solution for the high IOPS environment is shown in the figure here
Figure 2 VDI solution architecture
31 Software Horizon view Horizon View is a VDI solution that includes a complete suite of tools for delivering desktops as a secure
and managed service from a centralized infrastructure A Horizon View infrastructure consists of many
different software network and hardware layer components This section presents an overview of the key
Horizon View components and technologies that are critical for successful design and deployment of the
VDI environment
10 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
311 Horizon view components A functional list of Horizon View components used in this solution is given in the table here
Table 1 Horizon View components
Component Description
Client Devices Personal computing devices used by end users to run the Horizon View Client These can include special end-point devices such as Dell Wyse end points mobile phones and PCs
Horizon View Connection Server
A software service that acts as a broker for client connections by authenticating and then directing the incoming user requests to the appropriate virtual desktop physical desktop or terminal server
Horizon View Client Software that is used to access the Horizon View desktops
Horizon View Agent A service that runs on all systems used as sources for Horizon View desktops and facilitates network communication between the Horizon View clients and the Horizon View server
Horizon View Administrator
A web-based administration platform for the Horizon View infrastructure components
vCenterreg Server Central administration platform for configuring provisioning and managing VMware virtualized data centers
Horizon View Composer
A service running with Horizon View servers used to create pools of virtual desktops from a shared-base image to reduce storage capacity requirements
312 Virtual desktops Virtual desktops can be classified in to two major categories persistent and non-persistent
Persistent desktop environment All configuration and personalization on the assigned desktop is kept for
the user-between sessions When using persistent desktops an administrator usually has to provision
additional storage along with other administrative requirements such as patching and upgrading of
individual desktops
Non-persistent desktop environment Users are dynamically assigned virtual desktop VMs from a pool of
resources during login This type of virtual desktop does not retain any information between sessions At
logoff all changes are simply discarded and the virtual desktop is returned to the original state Patching
and upgrading non-persistent desktops requires only making the change to the base image and refreshing
or recomposing the virtual desktop pool Thus these desktops are much easier to manage but lack the
potential for persistent user customization
11 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
313 Horizon view desktop pools A desktop pool is a term VMware uses to describe a collection of desktops that are managed as a single
entity by the Horizon View Administrator interface Horizon View desktop pools allow administrators to
group users depending on the type of service the user requires There are two types of pools ndash Automated
and Manual
In Horizon View an Automated Pool is a collection of VMs cloned from a base template while a Manual
pool is created by the Horizon View Manager from existing desktop sources physical or virtual For each
desktop in the Manual pool the administrator selects a desktop source to deliver Horizon View access to
the clients
VMware View Personas profile management features can be used to achieve persistent desktop-like
behavior on non-persistent desktops By using these features an administrator can design a user account
where the configuration settings are written to a remote profile that is stored separately from the virtual
desktop image files This reduces the need for additional management on individual virtual desktops while
still providing a customized user experience
314 Using linked clones Significant storage space savings and increased efficiencies in desktop VM provisioning and administration
are possible when using VMware-linked clones A linked clone is a duplicate VM that shares the same base
image with the original VM but has separate differential data disks to track the differences from the
original one Each linked clone functions as an independent desktop VM with its own unique identity
Because linked clones share the same base image they consume significantly less storage disk space than
a set of completely independent VM images Temporary system data and other data unique to each linked
clone desktop VM are written to separate differential data storage and these temporary changes are
discarded during restart andor user logoff Persistent data such as user profiles applications and user
data can be optionally redirected to a CIFS share With this model software maintenance updates
antivirus remediation and patches need to be applied only on the base image These base image changes
automatically take effect on all linked clones without affecting any user settings and data
To configure linked clones the administrator creates a snapshot of a parent VM image with the required
OS settings and software installed Horizon View Composer first creates a full replica (clone) of the parent
VM and then uses this replica to create linked clones The replica can be placed on the same data store as
the linked clones or on a separate data store
More information about configuring linked clones can be found in the ldquoCreating Desktop Poolsrdquo section of
the VMware Horizon View Online Library here
315 Hypervisor platform VMware vSphere 55 VMware vSphere 55 is the enterprise virtualization platform used for building VDI and cloud
infrastructures VMware vSphere 55 includes three major layers virtualization management and interface
The virtualization layer includes infrastructure and application services The management layer is central
12 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
for configuring provisioning and managing virtualized environments The interface layer includes the
vSphere client and the vSphere web client
Throughout the solution all VMware and Microsoft best practices and prerequisites for core services were
used (NTP DNS Active Directory and others)
32 Hardware Dell infrastructure Figure 3 shows the design of the infrastructure for the Horizon Viewndashbased high IOPS type VDI
deployment that leverages Fluid Cache
An eight-node vSphere server cluster is used to host the virtual desktops Each of these server nodes has a
direct-attached PCIe SSD that is added to the Fluid Cache pool thus making each server a Fluid Cache
Provider (a server contributing to the Fluid Cache capacity) The eight PCIe SSDs were distributed among
all the servers to better balance the load on the Fluid Cache server Fluid Cache server1 These servers
were connected by using a private caching network to provide the Fluid Cache functionality Also the
servers were connected through a separate managementVDI client network and a 10 GB Ethernet iSCSI
SAN network
Another two-node vSphere server cluster is used to host the VDI infrastructure VMs such as vCenter
server View Connection server View Composer server SQL Server and Active Directory etc These
infrastructure servers were connected to the management network and the iSCSI SAN network
The Compellent storage array for the solution has two controllers and a mix of Write Intensive (WI) SSDs
15K SAS HDDs and 72K NL-SAS HDDs to provide the optimal performance and capacity needed for the
solution
Two switches are stacked together for different networks to provide redundancy in the networking layer
Ideally 40 GB Ethernet switches are recommended for the cache network While 1 GB Ethernet switches
can be used for management network it is better to use 10 GB Ethernet switches combining management
and VDI client networks The same 10 GB Ethernet switches can be used for iSCSI SAN also (with different
network traffic segmented by VLANs) provided they have adequate bandwidth needed for the specific VDI
deployment
Information about how this reference architecture was developed ensuring the optimal utilization across
the servers switches and storage arrays is discussed later in the following sections of this technical white
paper
1 Fluid Cache does not require all servers to be a Fluid Cache Provider For example in this case four
servers could have two PCIe SSDs each This configuration with four Fluid Cache Provider and four Fluid Cache Client would have had same capacity for Fluid Cache pool and all eight servers could have taken advantage of Fluid Cache However the chosen configuration for the technical white paper provides better performance the because VDI application caching load is unforming distributed among all the available servers
13 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 3 Infrastructure Set-up for VDI Solution
1 Enterprise Manager Console 2 Management and VDI Client Network 3 vSphere Servers hosting virtual desktops 4 Cache network switches (2)
5 SAN switch 6 Storage Center controllers (2) 7 Storage Center expansion enclosures (2) 8 Server hosting VDI infrastructure VMs
(Server 1) (Server 2)
14 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
4 Solution configuration This section provides information about the solution configuration and test setup for hosting Horizon View
virtual desktops including infrastructure components networking and storage subsystems
41 Host design considerations The entire VDI solution was installed in two vSphere server clusters The clusters included
Figure 4 vSphere server clusters
Infrastructure Cluster Two Dell PowerEdge R720 servers hosting VMs for Active Directory
services VMware vCenter 55 server Horizon View Connection server (primary and secondary)
View Composer server Microsoft Windows Server 2012 R2 based file server and SQL Server 2012
R2
View Client Cluster Eight Dell PowerEdge R720 servers hosting the virtual desktops Each server
had
o 2times10 core Intel Xeon CPU E5-2690v2 300GHz
o 256 GB RAM
o 1times350 GB Dell Express Flash PCIe SSD
o 1timesMellanox Connect ndash X3 card
o 1timesDual-port Broadcom NetXtreme II BCM57810 10 Gigabit NIC
o 1timesQuad-port Broadcom NetXtreme BCM5720 Gigabit NIC
Along with the other servers the above servers 40 LoginVSI launcher VMs were used to generate VDI
workload They can be hosted by two PowerEdge R720 servers or equivalent for VDI load generation
purposes
15 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
42 Network design considerations Figure 5 here shows the network layout of one of the eight PowerEdge R720 servers with vSphere 55
installed
Figure 5 vSphere host network configuration
Three network switches are used in the Fluid Cache for VDI implementation One Force10 S55 1 GB switch
for all management traffic and VDI traffic The management traffic includes hosts and vSphere
management Compellent storage management and so on The networks are segregated by using VLANs
to separate different types of traffic
One Dell Force10 S4810 10 GB switch is used for Fluid Cache cache network which supports all the traffic
between cache layer on eight VDI VM hosts Another Force10 S4810 10 GB switch is used for iSCSI
network between infrastructure hosts VDI VM hosts and Compellent SC8000
Appendix B has extended information on the vSwitch configuration for each vSphere host
16 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
43 Dell Compellent SC8000 storage array configurations The storage used to host the virtual desktops was a Dell Compellent SC8000 array running Storage Center
Operating System (SCOS) 65 All two front-end ports were 10 GB iSCSI and all two back-end ports were
six GB serial-attached SCSI (SAS) The array used two external enclosures with Write Intensive (WI) SSDs
comprising Tier 1 and 15K SAS HDDs comprising Tier 2 for performance Also 72 NL-SAS drives were
used in Tier 3 to provide capacity for user data Table 2 summarizes the storage hardware configuration
Table 2 Storage hardware components
Storage role Type Qty Description
Controllers SC8000 2 System Center Operating System (SCOS) 65
Enclosures External 2 24 bay ndash 25rdquo disk drive enclosure
Ports Ethernet ndash 10 Gbps 2 Front end host connectivity
SAS - 6 Gbps 4 Back end drive connectivity
Drives 400 GB WI SSD 12 11 active with 1 hot spare
300 GB 15K SAS HDD
21 20 active with 1 hot spare
4 TB 72K NL-SAS HDD
12 11 active with 1 hot spare
The volumes created to host the virtual desktops took advantage of the Compellent Dynamic Capacity
technology for efficient capacity allocation Table 3 lists the volume layout used for the infrastructure
functions including user data
Table 3 Volume layout for hosting infrastructure components and user data
Volume name Size Purpose
Infrastructure 500 GB Storage for Active Directory SQL Server vCenter Server View Connection Server View Composer and File Server
UserSpace 2 TB Storage for User profiles and folder redirection space (Average 25 GB per user)
Along with the infrastructure volumes the storage array also provided shared storage for hosting the
virtual desktops The volume layout used for configuring the base image (View Composer Replica) and VDI
volumes on the array is shown in Table 4
17 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 4 Dell Storage PS4210XS layout for volumes hosting virtual desktops
Volume name Size Purpose
View-Replicas1 and 2 100 GB each Storage for base image for VDI deployment
VDI-Images1 through 8 500 GB each Storage for VDI VMs in VDI Cluster Each volume hosted 100 desktops
44 vSphere host network configuration VMware vSphere 55 hypervisor was installed on all servers The network configuration on each of those
hosts is described here Each vSphere host was configured with five virtual switches vSwitch0 vSwitch1
vSwitch2 vSwitch3 and vSwitch4 to separate different types of traffic on the system
Table 5 vSwitch configuration in vSphere hosts
vSwitch Description
vSwitch0 Management Network
vSwitch1 and vSwitch2 iSCSI SAN
vSwitch3 Fluid Cache VLAN
vSwitch4 VDI LAN
For additional information about individual vSwitch configuration refer to Appendix B in the Dell technical
white paper
45 Horizon view configuration Horizon View 60 was installed by using the documentation provided by VMware
Horizon View 601 installation documentation
httpswwwvmwarecomsupportpubsview_pubshtml
Table 6 Specific configuration used in the tests
Purpose Count Type Memory CPU
Horizon View Connection Servers
2 VM 16 GB 8nos
View Composer Server 1 VM 8 GB 8nos
18 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
46 Windows 7 VM configuration Following the guidelines from VMware and Login VSI the Windows 7 base image was generated based on
a generic base VM with the following properties
VMware Virtual Hardware version 8
Two virtual CPU
3 GB RAM with 15GB reserved
25 GB virtual hard drive
One virtual NIC connected to the VDI network
Windows 7 64-bit OS
Also the base image was customized by using the VMware Horizon with View Optimization Guide for
Windows 7 and Windows 8 available at this location httpwwwvmwarecomfilespdfVMware-View-
OptimizationGuideWindows7-ENpdf
19 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
5 Horizon view test methodology This section outlines the test objectives along with the test tools and criteria used to determine the
optimal virtual desktop density and best practices for deploying Horizon View on Dell Fluid Cache for SAN
for high IOPS type VDI environment
51 Test objectives As noted in Section 11 the test objectives were
Develop an optimal end-to-end infrastructure design for a Horizon View and vSpherendashbased high
user type of VDI solution deployed by using the Fluid Cache Compellent storage PowerEdge
servers and Dell Networking switches
Determine the performance at every layer of the VDI solution stack under high IOPS workload For
example desktops generating 80ndash90 IOPSVM at steady state
Determine the performance impact of peak IO activity such as boot and login storms
52 Test tools All tests were conducted by using Login VSI 40 as the workload generator and user experience analyzer
tool Login VSI is a benchmarking tool to measure the performance and scalability of centralized desktop
environments such as Server Based Computing (SBC) and VDI
Note More information can be found at the Login VSI website httpwwwloginvsicom
In addition to Login VSI Iometer is used in desktop VMs to simulate high IOPS conditions Iometer is
invoked in desktop VMs by using custom scripting of Login VSI workloads
Note More information can be found at the Iometer project website httpwwwiometerorg
521 Load generation First the ldquoMediumrdquo workload from Login VSI was used to simulate the standard user workload The
characteristics of the Medium workload are
Up to five applications are started simultaneously
Applications include Microsoft Internet Explorer Microsoft Word Microsoft Excel Microsoft
PowerPoint PDF reader 7-Zip compression software Movie player and FreeMind
After a session is started the medium workload repeats approximately after every 48 minutes
During a loop the response time is measured after every 3ndash4 minutes
Idle time is about two minutes in each 48-minute loop
Type rate is approximately 160 milliseconds per character
After the test by using Login VSI Medium was complete tests were rerun with Login VSI Medium and
Iometer in desktop VMs to simulate high IOPS VDI workload While the Login VSI Medium generates 8ndash10
20 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
IOPSVM the latter method was able to generate 80ndash90 IOPSVM For these tests each VM in the Horizon
view pool is created with standard LoginVSI contents and applications Also Iometer is installed on each
VM After the user logs in a customized logon script starts the Iometer with required IO specification (icf
file)
522 Monitoring tools The following monitoring tools were used
Dell Compellent Enterprise Manager for monitoring Fluid Cache and Compellent SC8000 storage
array performance
VMware vCenter statistics for vSphere performance
Login VSI Analyzer for end user performance statistics
Detailed performance metrics were captured from the storage arrays hypervisors virtual desktops and
the load generators during the tests
53 Test criteria The primary focus of the tests is to validate the 800 desktop high IOPS type of VDI architecture with
acceptable user experience by using Fluid Cache for SAN VDI configurations involve many components at
different layers ndash application hypervisor server network and storage As a result multiple metrics need to
be captured at different layers to ensure that the environment is healthy and performing optimally and
appropriately for all users
The specific test criteria are described in the following sections
531 Storage capacity and IO latency The typical industry standard latency limit for storage disk IO is 10 milliseconds Maintaining this limit
ensures good user application response times when there are no other bottlenecks at the infrastructure
layer In addition Dell recommends to maintain a 10 percent spare disk space on the storage array for
optimal performance
532 System utilization at the hypervisor Even though the primary focus of these tests was storage characterization additional metrics at the
hypervisor infrastructure layer were defined to ensure solution consistency These were
CPU utilization on any vSphere server must not exceed 85 percent
Minimal memory ballooning on the VMs
Total network bandwidth utilization must not exceed 90 percent on any one link
TCPIP storage network retransmissions should be less than 05 percent
21 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
533 Virtual desktop user experience Login VSI Analyzer was also used to gather metrics on the user experience at the virtual desktop layer to
ensure that all the desktops had acceptable levels of application performance Login VSI uses the VSImax
parameter to determine the maximum number of sessions that can be obtained from a deployed solution
The calculation methodology used in VSImax is available here
httpwwwloginvsicomdocumentationindexphptitle=Analyzing_Results
534 Test configuration A single virtual desktop pool was configured by using the VMware Horizon View Administrator interface
Each pool was built from a Windows 7 base image The Windows 7 configuration information is available
in Section 46
Desktop pool properties
Automatic Desktop Pool
Users are assigned using Floating assignments
View Storage Accelerator is enabled for all hosts with a refresh period of seven days
800 desktops were deployed across eight hosts (100 desktops a host)
Replica images were stored on a separate volume
22 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
6 Test results and analysis This section presents the results from the different Horizon View VDI characterization tests and the key
findings from each test The testing was focused on the high IOPS workload profile
61 Test scenarios The following tests were conducted to gather results and analysis on the solution stack
1 Boot storm Boot storms represent the worst-case scenario where many virtual desktops are
turned on at the same time and they all contend for the system resources simultaneously This test
was used to evaluate if the storage array hosting the desktops was capable of handling huge
variation in storage IO without causing significant impact on other services
2 Login storm Login storms also represent a high IOPS situation where many users are logging in to
their virtual desktops at the beginning of a workday or a shift In this test all the desktops were
pre-booted and left in an idle state for more than 20 minutes to let their IO settle before running
the Login VSI Medium workload to simulate users logging in to their virtual desktops
3 Steady state workload for standard users with normal IOPS After the login storm for the previous
test was completed the Login VSI Medium workload was allowed to run for at least one hour to
simulate the real-world scenario of users performing their daily tasks The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
4 Steady state workload for users with high IOPS The previous test was repeated with the Login
VSI Medium workload and Iometer scripts in desktop VMs as described in Section 521 to simulate
real-world heavy users performing their daily tasks with high IOPS The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
The following sections provide results from the boot storm login storm and steady state testing for the
Fluid Cache for SAN based VDI solution
23 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
62 Boot storm IO To simulate a boot storm the virtual desktops were reset simultaneously from the VMware vSphere client
Figure 6 shows the IO pattern on the Fluid Cache for the boot storm
Figure 6 SAN HQ data showing boot storm performance with Fluid Cache array
With 800 desktops the boot storm generated about 115000 total IOPS with a majority of them being
write operations All desktops were available for use in less than four minutes
24 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
63 Login storm and steady state for standard users (LoginVSI
Medium) Login VSI was programmed to start 800 virtual desktops over a period of about 60 minutes after pre-
booting the virtual desktops The peak IOPS during the login storm observed by the vSphere servers
hosting the desktops was about 6500 IOPS (8ndash10 IOPS a VM)
In a standard user environment login storms generate significantly more write IOPS than a boot storm or
steady state because of multiple factors such as
User profile activity
Starting operating system services on the desktop
First start of applications
After a virtual desktop has achieved a steady state after user login the Windows 7 OS has cached
applications in memory and does not need to access storage each time the application is started This
leads to lesser IOPS during the steady state Figure 7 here shows the various IO characteristics during the
login storm and steady state of these tests
25 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 7 IOPS and Cache Hit for the standard user test
On the Fluid Cache layer the maximum IOPS reached 6500 with cache-hit reaching 100 percent and
read-hit around 95 percent As shown in the Figure 8 here the throughput peaked at 98 MBps with a low
latency of less than 2 msec
26 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 8 Throughput and Latency for the standard user test
631 Server host performance During the login storm and steady state of the test the vSphere host CPU memory network and storage
performance were measured on all the servers that hosted the virtual desktops The performance of one
such vSphere server is given here The other vSphere servers had similar performance characteristics
Statistics for the vSphere hosts were captured by using VMware vCenter Server The figures here show the
CPU memory and network utilization for boot storm login storm and steady state of one of the vSphere
servers hosting the virtual desktops The results shown here are for a test run with 800 no standard user
desktops in the desktop pool
27 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 9 Average CPU performance per core on one vSphere host during login storm and steady state
Figure 10 Disk space usage during login storm and steady state
0
10
20
30
40
50
60
70
80
90
100
1020 1045 1110 1135 1200 1225
Per
cen
t
Time
CPU Performance
0
50
100
150
200
250
300
1020 1040 1100 1120 1140 1200 1220
GB
Time
Memory Performance
Granted Swap used Shared common
28 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 11 Overall network performance during login storm and steady state
Figure 12 Storage adapter performance during login storm and steady state
0
10000
20000
30000
40000
50000
60000
70000
1020 1045 1110 1135 1200 1225
kBp
s
Time
Network Performance
0
05
1
15
2
25
1020 1045 1110 1135 1200 1225
mSe
c
Time
Storage adaptor performance
29 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
The key observations from the statistics were
CPU utilization was less than the 85 percent threshold throughout the test
Active disk space usage was about 80 percent during the boost storm and about 60 percent
during login storm and steady state There was minimal-or no memory ballooning observed
Network utilization was about 45 percent which included all the networks such as iSCSI SAN VDI
LAN Management LAN and vMotion LAN
Average read- and write latencies at the storage adapter level were very close to the observed
latencies in Fluid Cache 2 msec
632 Monitoring user experience Figure 13 here shows the response time as experienced by each user as calculated by Login VSI The graph
clearly shows that the VSImax (Dynamic) value has not been reached and there were non-responsive or
inactive sessions This means that the array is capable of supporting the 1000 desktops and all users have
acceptable response times for applications that the user is has started
Figure 13 Login VSI user experience monitoring for 800 standard user desktops
30 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
633 Standard user test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SANndashbased VDI solution is able to host 800 virtual desktops and support
a standard user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only operations and
less than 2 percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to handle this login storm easily with low latency mdash it delivered the required 6500 IOPS with less
than 2 milliseconds of write latency with a 99 percent write VDI IO workload
64 Login storm and steady state with high IOPS (LoginVSI Medium +
Iometer) As mentioned earlier Iometer was used in desktop VMs alongside the Login VSI Medium workload to
simulate high IOPS type of VDI environment To mimic actual VDI workload profile the following Iometer
profile was used
20 KB block size 80 percent write 75 percent random with 25 msec burst delay
Figure 14 here shows the various IO characteristics during the login storm and steady state of these tests
Figure 14 IOPS and Cache Hit for the high IOPS test
On the Fluid Cache layer the maximum IOPS reached was approximately 72000 (or 90 IOPSVM) with
cache write-hit 100 percent and read-hit around 95 percent As shown in the Figure 15 the throughput
peaked at greater than 900 MBps with a peak latency of approximately 75 msec
31 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 15 Throughput and Latency for the high IOPS test
32 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
641 Server host performance Similar to the standard user test statistics for the vSphere hosts were captured by using VMware vCenter
Server during the high IOPS (heavy user) test also There are no significant differences in CPU disk space
and network utilization between standard users and heavy users The storage adapter latency is also
showing similar on hosts and observed on Fluid Cache
642 User experience monitoring Figure 16 here shows the response time as experienced by each user as calculated by Login VSI for the
heavy user test The graph shows that the VSImax (Dynamic) value was 796 indicating that the solution is
capable of supporting the 800 user high IOPS desktops with 90 IOPSVM
Figure 16 Login VSI user experience monitoring for 800 user high IOPS desktops
33 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
643 High IOPS (heavy user) test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SAN based VDI solution is able to host 800 virtual desktops and support a
high user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only and less than 2
percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to easily handle this login storm with low latency Subsequently it was able to handle 72000 IOPS
at high IOPS steady state with 90 IOPSVM with a maximum of 75 msec latency
34 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
7 Best practices This section provides the best practices derived from the testing and analysis in Section 6
71 Virtual Desktop Infrastructure This section provides best practices for the implementation of VDI using Dell Fluid Cache for SAN
711 Implement roaming profiles and folder redirection Dell recommends that all users in the VDI environment be configured with roaming profiles and folder
redirection This preserves user profiles and user data across boots while using non-persistent virtual
desktops
Also Dell recommends to use a high performance file service to provide the profile and folder redirection
A separate array may be used to host these volumes for best performance
712 Boot and login storm considerations Section 62 demonstrated the Fluid Cache for SAN performance under boot storm To avoid any potential
IO bursts because of boot storm and degraded user experience and performances Dell recommends that
all or portion of desktops be prebooted Connection brokers such as VMware Horizon View provide the
functionality to configure number of standby desktops
713 Windows 7 master image for desktop VMs Dell recommends that the operating system be customized in order to provide the best performance in a
VDI environment This includes disabling some services which may not be required This can improve
performance for the end user VMware has a specific set of recommendations and settings for Windows 7
and Windows 8 that allow for faster logins quicker screen refreshes and generally better performance
The VMware recommendations for Windows 7 and Windows 8 image optimization can be found here
httpwwwvmwarecomresourcestechresources10157
714 VDI Management infrastructure recommendations Dell recommends to have redundancy and load balancing for all VDI management services in the case of
VMware Horizon View solution as tested here the vSphere Server VMware Horizon View Servers and SQL
Servers Ideally these should be running on clustered hosts with VMware vSphere DRS (distributed
resource scheduler) and HA (high availability) enabled
72 Server host The vSphere servers hosting the infrastructure service providers and the virtual desktops are
recommended to be configured as follows
35 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Follow VMware and Dell best practices for installing and configuring vSphere
Separate virtual switches to segregate iSCSI SAN traffic VDI traffic vMotion traffic and Management
network traffic
Each network path must be assigned to a minimum of two physical NICs for high availability
VMware Knowledge Base article about best practices for installing vSphere 55
httpkbvmwarecomkb2052329
73 Network layer Dell recommends that at least two physical NICs on each vSphere server be dedicated to the VDI network
Use VLANs to segregate different types of network traffic on the same physical network In this case Dell
recommends to separate the infrastructure vMotion and VDI LAN traffic in to separate VLANs
Do not use VLANs to segregate iSCSI SAN and Fluide Cache traffic It is required that SAN and Cache traffic
be on separate dedicated physical network to provide the best performance
Virtual switches in vSphere have a default limit of 120 ports If the number of virtual desktops on each host
exceeds the available ports vSwitch properties should be changed to support the required number of
virtual desktops This change requires a restart of the host vSphere server
On iSCSI SAN switches Spanning tree must be disabled on switch ports connected to end devices for
server and storage ports The PortFast setting must be enabled in the switch configuration for these ports
Jumbo frames and Flow control (if the NICs support it) should be enabled for all components of the iSCSI
network
More information about configuring Dell Networking switches for use with Dell Storage iSCSI SANs is
available here
httpencommunitydellcomtechcenterstoragewwiki4250switch-configuration-guides-by-sisaspx
74 Storage The Dell SC storage arrays combined with Fluid Cache is an excellent platform for providing cost-effective
performance in VDI environments
Fluid Cache for SAN extends the power of Compellent intelligent data placement from the SAN to the
server By providing a single infrastructure for data at both high- and low ends of the performance
spectrum Fluid Cache for SAN with Storage Center 65 array software eliminates the tradeoffs between
server performance and full-featured SAN benefits such as reliability manageability and data protection
Dell recommends to have separate volumes for base image and virtual desktops This enables better
manageability of the volumes easier performance monitoring and allows easy future growth
Dell recommends to use a separate high performance file service to provide file shares for roaming
profiles and user shares
36 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
8 Conclusion The technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed by using a Horizon View VDI platform leveraging Dell Fluid Cache for SAN The storage IO
characteristics under various VDI workload scenarios (boot storm login storm and steady state) along
with performance characteristics throughout the VDI stack (for example vSphere server performance and
user experience) demonstrate the optimal configuration of the infrastructure used for this VDI
deployment For more information about Fluid Cache contact your Dell account manager
37 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
A Horizon view solution configuration
Table 7 Hardware components
Hardware components Description
Virtual Desktops 4 timesDell PowerEdge R720 Servers (Fluid Cache Providers)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
2times350 GB Dell Express Flash PCIe SSDs
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
4 x Dell PowerEdge R720 Servers (Fluid Cache Clients)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55 U2 on all R720 servers Windows 7 (64 Bit) VMs
Infrastructure Servers 2 x Dell PowerEdge R720 servers
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
96 GB RAM
2times300 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55U2 on all R720 servers VMs are loaded with Microsoft Windows 2008 R2
Active Directory
VMware Horizon View 60 Server 1
VMware Horizon View 60 Server 2
VMware vCenter Server 55 update 2
VMware Horizon View Composer
SQL Server
File Server
Login VSI Launchers 8 x Dell PowerEdge M610 servers
2timesIntelreg Xeonreg E-5503 200 GHz Processors
16 GB RAM
4times146 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57711 10GbE NIC
ESXi 51 installed on all R810 servers VMs are loaded with Microsoft Windows 7 64bit Each VM supports up to 30 Login VSI launcher sessions
38 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Network Management VDI LAN
1timesDell Force10 S55 1Gb Ethernet Switch
iSCSI SAN
1timesDell Force10 S4810 10Gb Ethernet Switch
Cache network
1timesDell Force10 S4810 10Gb Ethernet Switch
One Force10 S4810 switch might suffice for all the cache iSCSI SAN VDI LAN and management traffic
Storage 2timesDell Compellent SC8000 controllers 4times6Gb SAS 4-port PCI-E Full-height cards for back-end connectivity 2times10Gb iSCSI 2 port PCI-E Low-profile IO cards for front end connectivity 1timesDell Compellent SC200 disk enclosures 12times4TB NL-SAS 6Gb 72K 35rdquo drives
User Data Infrastructure VMs Virtual Desktops
Performance Monitoring
Dell Compellent Enterprise Manager Dell Fluid Cache for SAN performance monitoring tool () vCenter Performance monitoring Liquidware Stratusphere UX
Performance monitoring on Compellent arrays Fluid Cache performance monitoring Performance monitoring and capture at the ESXi host User experience monitoring on the virtual desktop
39 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 8 Software components
Software components Description Version
Dell Fluid Cache for SAN 20
Dell Compellent Storage Center 64
Dell Compellent Enterprise Manager 64
VMware Horizon View Server 60
VMware Horizon View Composer 60
VMware Horizon View Agent 60
VMware Horizon View Client 64-bit 60
VMware ESXi Hypervisor 55 U2
VMware vCenter Server 55 U2
Microsoft SQL Server 2008R2 Enterprise x64 105016001
Client VM OS Microsoft Windows 7 Enterprise x64 SP1
Management VM OS Microsoft Windows Server 2008 Enterprise R2 x64 SP1
Microsoft Office MS office 2010 Standard Service Pack 1
Login VSI Version 40
Iometer 20060727
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
2 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Revisions
Date Description
January 2015 Initial release
THIS WHITE PAPER IS FOR INFORMATIONAL PURPOSES ONLY AND MAY CONTAIN TYPOGRAPHICAL ERRORS AND
TECHNICAL INACCURACIES THE CONTENT IS PROVIDED AS IS WITHOUT EXPRESS OR IMPLIED WARRANTIES OF
ANY KIND
copy 2015 Dell Inc All rights reserved Reproduction of this material in any manner whatsoever without the express
written permission of Dell Inc is strictly forbidden For more information contact Dell
PRODUCT WARRANTIES APPLICABLE TO THE DELL PRODUCTS DESCRIBED IN THIS DOCUMENT MAY BE FOUND
AT httpwwwdellcomlearnusen19terms-of-sale-commercial-and-public-sector Performance of network
reference architectures discussed in this document may vary with differing deployment conditions network loads and
the like Third party products may be included in reference architectures for the convenience of the reader Inclusion
of such third party products does not necessarily constitute Dellrsquos recommendation of those products Please consult
your Dell representative for additional information
Trademarks used in this text
Delltrade the Dell logo Dell Boomitrade Dell Precisiontrade OptiPlextrade Latitudetrade PowerEdgetrade PowerVaulttrade
PowerConnecttrade OpenManagetrade EqualLogictrade Compellenttrade KACEtrade FlexAddresstrade Force10trade and Vostrotrade are
trademarks of Dell Inc Other Dell trademarks may be used in this document Cisco Nexusreg Cisco MDSreg
Cisco NX-
0Sreg
and other Cisco Catalystreg
are registered trademarks of Cisco System Inc EMC VNXreg
and EMC Unispherereg
are
registered trademarks of EMC Corporation Intelreg
Pentiumreg
Xeonreg
Corereg
and Celeronreg
are registered trademarks of
Intel Corporation in the US and other countries AMDreg
is a registered trademark and AMD Opterontrade AMD
Phenomtrade and AMD Semprontrade are trademarks of Advanced Micro Devices Inc Microsoftreg
Windowsreg
Windows
Serverreg
Internet Explorerreg
MS-DOSreg
Windows Vistareg
and Active Directoryreg
are either trademarks or registered
trademarks of Microsoft Corporation in the United States andor other countries Red Hatreg
and Red Hatreg
Enterprise
Linuxreg
are registered trademarks of Red Hat Inc in the United States andor other countries Novellreg
and SUSEreg
are
registered trademarks of Novell Inc in the United States and other countries Oraclereg
is a registered trademark of
Oracle Corporation andor its affiliates Citrixreg
Xenreg
XenServerreg
and XenMotionreg
are either registered trademarks or
trademarks of Citrix Systems Inc in the United States andor other countries VMwarereg
Virtual SMPreg
vMotionreg
vCenterreg
and vSpherereg
are registered trademarks or trademarks of VMware Inc in the United States or other
countries IBMreg
is a registered trademark of International Business Machines Corporation Broadcomreg
and
NetXtremereg
are registered trademarks of Broadcom Corporation Qlogic is a registered trademark of QLogic
Corporation Other trademarks and trade names may be used in this document to refer to either the entities claiming
the marks andor names or their products and are the property of their respective owners Dell disclaims proprietary
interest in the marks and names of others
3 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Contents Revisions 2
Executive summary 5
1 Introduction 6
11 Objectives 6
111 Audience 6
2 Dell Fluid Cache for SAN and VDI 7
3 Solution architecture 9
31 Software Horizon view 9
311 Horizon view components 10
312 Virtual desktops 10
313 Horizon view desktop pools 11
314 Using linked clones 11
315 Hypervisor platform VMware vSphere 55 11
32 Hardware Dell infrastructure 12
4 Solution configuration 14
41 Host design considerations 14
42 Network design considerations 15
43 Dell Compellent SC8000 storage array configurations 16
44 vSphere host network configuration 17
45 Horizon view configuration 17
46 Windows 7 VM configuration 18
5 Horizon view test methodology 19
51 Test objectives 19
52 Test tools 19
521 Load generation 19
522 Monitoring tools 20
53 Test criteria 20
531 Storage capacity and IO latency 20
532 System utilization at the hypervisor 20
533 Virtual desktop user experience 21
534 Test configuration 21
4 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
6 Test results and analysis 22
61 Test scenarios 22
62 Boot storm IO 23
63 Login storm and steady state for standard users (LoginVSI Medium) 24
631 Server host performance 26
632 Monitoring user experience 29
633 Standard user test results summary 30
64 Login storm and steady state for heavy users (LoginVSI Medium + Iometer) 30
641 Server host performance 32
642 User experience monitoring 32
643 Heavy user test results summary 33
7 Best practices 34
71 Virtual Desktop Infrastructure 34
711 Implement roaming profiles and folder redirection 34
712 Boot and login storm considerations 34
713 Windows 7 master image for desktop VMs 34
714 VDI Management infrastructure recommendations 34
72 Server host 34
73 Network layer 35
74 Storage 35
8 Conclusion 36
A Horizon view solution configuration 37
B vSphere host network configuration 40
B1 vSwitch ndash Management traffic 40
B2 vSwitch - iSCSI 40
B3 vSwitch ndash Fluid Cache network 41
B4 vSwitch3 41
Additional resources 42
Acknowledgements 43
Feedback 43
5 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Executive summary
A Virtual Desktop Infrastructure (VDI) deployment can place high storage capacity and performance
demands on the storage platform For example consolidating large amounts of inexpensive stand-alone
desktop storage in to a centralized infrastructure can create tremendous storage capacity demands on
centrally managed shared storage used in VDI deployments Performance demands are determined by
the number of IO operations per second (IOPS) generated by basic desktop client operations such as
system boot logon and logoff and by desktop usage operations from different users Storm events such
as simultaneous booting of many desktops morning logons and afternoon logoffs by many users at
approximately the same time and virus scan can cause IO requirement variances that place high
performance demands on the storage infrastructure
Current VDI solutions in the market can cost-effectively manage desktop virtualization use cases where
performance demands are not really demanding For example a task worker environment in a call center
can generate 5ndash10 IOPSVM or a knowledge worker environment in an office can generate 15ndash25
IOPSVM Typically hybrid arrays or all-flash arrays are deployed to accommodate performance needs in
these VDI environments
The next frontier for VDI to conquer is the high IOPS use cases such as a software developer organization
or an engineering CADCAM team In these use cases not only the capacity demands are large
(repositories for code or design in development) but also performance demands are extremely high
(often 50ndash80 IOPSVM)
Dell Fluid Cache for SAN mdashan innovative server-side readwrite caching solution for workload
acceleration can provide an innovative cost-effective solution for high IOPS type VDI environments
Even though these VDI environments need a lot of storage capacity the working set is typically relatively
small However this working set is very IO intensivemdashmore read operations (write operations) during
boot storms and more write-operations during steady state Fluid Cache software can provide extremely
high IOPS with minimal latency for these working set VDI data leveraging PCIe SSDs as readwrite cache
pool in the computational tier while a Dell Compellent SAN storage array can provide the performance
and large capacity needed for the shared storage This combination fits perfectly for high IOPS VDI
environment
This technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed in a VMware Horizon View VDI infrastructure leveraging Fluid Cache and Compellent storage
array The test infrastructure also included Dell Networking switches and Dell PowerEdge servers running
VMware vSphere 55 as the hypervisor In the test environment the solution infrastructure successfully
hosted 800 desktops with satisfactory performance results across all layers of the stack including the
user layer hypervisor layer and storage layer while delivering approximately 90 IOPSVM as a sustained
steady state load Fluid Cache performance ensured excellent end-user desktop application response
times as determined by the user-level experience monitoring software LoginVSIrsquos VSIMax Details are
provided for the storage IO characteristics about various VDI workload scenarios such as boot and login
storms along with performance characteristics throughout the VDI stack
6 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
1 Introduction Desktop virtualization platforms such as VMware Horizon View 60 (Horizon View) can provide
organizations with significant cost savings streamlined implementation and ease of desktop
management In order to achieve these VDI benefits and to ensure optimal user experience the end-to-
end infrastructure design and sizing considerations need to be addressed carefully While VDI workloads
for task and knowledge workers are correctly understood by using many cost-effective solutions that are
available the high IOPS 800-user VDI use cases are addressed less often because current solutions
typically do not meet the stringent performance- and capacity requirements of these use cases in an
economically sensible manner
The goal of this technical white paper is to present the results of a series of storage IO performance tests
and provide the optimal end-to-end infrastructure design for high IOPS 800-user type VDI environments
leveraging Dell Fluid Cache for SAN Dell Compellent SAN storage arrays Dell PowerEdge servers and Dell
Networking switches
11 Objectives The primary objectives of the tests conducted for this technical white paper are
Develop an optimal end-to-end infrastructure design for a Horizon View and vSphere-based
heavy user type VDI solution deployed by using the Fluid Cache Compellent storage PowerEdge
servers and Dell Networking switches
Determine the performance at every layer of the VDI solution stack under high IOPS workload For
example desktops generating 80ndash90 IOPSVM at steady state
Determine the performance impact of peak IO activity such as boot and login storms
The test infrastructure used for the tests included
VMware Horizon View 60
VMware vSphere 55 hypervisor
Dell PowerEdge R720 servers with Dell Express PCIe SSDs
Dell Networking S4810 switches
Dell Compellent SC8000 storage array
111 Audience This technical white paper is intended for solution architects storage network engineers system
administrators and IT managers who need to understand about designing properly sizing and deploying
Horizon View-based VDI solutions by using Dell infra design properly sizing and deploying Horizon View-
based VDI solutions by using Dell infrastructure It is expected that the reader has a working knowledge of
the Horizon View architecture vSphere system administration iSCSI SAN network design and Dell
Compellent SAN operation
7 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
2 Dell Fluid Cache for SAN and VDI Dell Fluid Cache for SAN utilizes direct-attached Dell PowerEdge Express Flash NVMe PCIe SSDs and
remote direct memory access (RDMA) networking capabilities to create a clustered caching pool for
improved storage workload performance Applications write directly to the cache pool the
acknowledgement is sent back to the application and in the background the IO is flushed to the external
storage array Data is copied in to the cache pool when it is accessed (read) by application and is available
from the cache pool for reread operations Also data that is written into the cache pool by the application
is then available for reread operations from the application A high-speed link to other cache nodes in the
Fluid Cache for SAN pool allows the data to remain highly available by replicating blocks of data even if a
single node in cache pool stops working Fluid Cache for SAN provides a single management interface and
provides other capabilities such as cache-aware snapshots and replication and compression
Figure 1 shows an example environment highlighting how Fluid Cache for SAN communicates between
server and storage Three nodes are required to run Dell Fluid Cache for SAN software Two of these three
nodes are required to have a minimum of one Dell PowerEdge Express Flash NVMe PCIe SSD each and
the network for private cache network is based on the low-latency RDMA protocol The RDMA network
handles the cache pool communication between the nodes Creation and management of the Fluid
Cache cluster are accomplished by using the Dell Compellent Enterprise Manager software through
automatic cache server discovery
Figure 1 Dell Fluid Cache for SAN communication
8 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Fluid Cache for SAN is an ideal solution for high IOPS type VDI environment with highly write-intensive
workloads because it provides extremely fast and low-latency server-side write back caching Because
writes are mirrored across high-speed network and later destaged to the SAN with significant write
coalescing this solution can sustain significantly higher IOPSVM than an external hybrid or all-flash array
ndashbased solution could
9 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
3 Solution architecture The overall architecture of the VDI solution for the high IOPS environment is shown in the figure here
Figure 2 VDI solution architecture
31 Software Horizon view Horizon View is a VDI solution that includes a complete suite of tools for delivering desktops as a secure
and managed service from a centralized infrastructure A Horizon View infrastructure consists of many
different software network and hardware layer components This section presents an overview of the key
Horizon View components and technologies that are critical for successful design and deployment of the
VDI environment
10 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
311 Horizon view components A functional list of Horizon View components used in this solution is given in the table here
Table 1 Horizon View components
Component Description
Client Devices Personal computing devices used by end users to run the Horizon View Client These can include special end-point devices such as Dell Wyse end points mobile phones and PCs
Horizon View Connection Server
A software service that acts as a broker for client connections by authenticating and then directing the incoming user requests to the appropriate virtual desktop physical desktop or terminal server
Horizon View Client Software that is used to access the Horizon View desktops
Horizon View Agent A service that runs on all systems used as sources for Horizon View desktops and facilitates network communication between the Horizon View clients and the Horizon View server
Horizon View Administrator
A web-based administration platform for the Horizon View infrastructure components
vCenterreg Server Central administration platform for configuring provisioning and managing VMware virtualized data centers
Horizon View Composer
A service running with Horizon View servers used to create pools of virtual desktops from a shared-base image to reduce storage capacity requirements
312 Virtual desktops Virtual desktops can be classified in to two major categories persistent and non-persistent
Persistent desktop environment All configuration and personalization on the assigned desktop is kept for
the user-between sessions When using persistent desktops an administrator usually has to provision
additional storage along with other administrative requirements such as patching and upgrading of
individual desktops
Non-persistent desktop environment Users are dynamically assigned virtual desktop VMs from a pool of
resources during login This type of virtual desktop does not retain any information between sessions At
logoff all changes are simply discarded and the virtual desktop is returned to the original state Patching
and upgrading non-persistent desktops requires only making the change to the base image and refreshing
or recomposing the virtual desktop pool Thus these desktops are much easier to manage but lack the
potential for persistent user customization
11 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
313 Horizon view desktop pools A desktop pool is a term VMware uses to describe a collection of desktops that are managed as a single
entity by the Horizon View Administrator interface Horizon View desktop pools allow administrators to
group users depending on the type of service the user requires There are two types of pools ndash Automated
and Manual
In Horizon View an Automated Pool is a collection of VMs cloned from a base template while a Manual
pool is created by the Horizon View Manager from existing desktop sources physical or virtual For each
desktop in the Manual pool the administrator selects a desktop source to deliver Horizon View access to
the clients
VMware View Personas profile management features can be used to achieve persistent desktop-like
behavior on non-persistent desktops By using these features an administrator can design a user account
where the configuration settings are written to a remote profile that is stored separately from the virtual
desktop image files This reduces the need for additional management on individual virtual desktops while
still providing a customized user experience
314 Using linked clones Significant storage space savings and increased efficiencies in desktop VM provisioning and administration
are possible when using VMware-linked clones A linked clone is a duplicate VM that shares the same base
image with the original VM but has separate differential data disks to track the differences from the
original one Each linked clone functions as an independent desktop VM with its own unique identity
Because linked clones share the same base image they consume significantly less storage disk space than
a set of completely independent VM images Temporary system data and other data unique to each linked
clone desktop VM are written to separate differential data storage and these temporary changes are
discarded during restart andor user logoff Persistent data such as user profiles applications and user
data can be optionally redirected to a CIFS share With this model software maintenance updates
antivirus remediation and patches need to be applied only on the base image These base image changes
automatically take effect on all linked clones without affecting any user settings and data
To configure linked clones the administrator creates a snapshot of a parent VM image with the required
OS settings and software installed Horizon View Composer first creates a full replica (clone) of the parent
VM and then uses this replica to create linked clones The replica can be placed on the same data store as
the linked clones or on a separate data store
More information about configuring linked clones can be found in the ldquoCreating Desktop Poolsrdquo section of
the VMware Horizon View Online Library here
315 Hypervisor platform VMware vSphere 55 VMware vSphere 55 is the enterprise virtualization platform used for building VDI and cloud
infrastructures VMware vSphere 55 includes three major layers virtualization management and interface
The virtualization layer includes infrastructure and application services The management layer is central
12 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
for configuring provisioning and managing virtualized environments The interface layer includes the
vSphere client and the vSphere web client
Throughout the solution all VMware and Microsoft best practices and prerequisites for core services were
used (NTP DNS Active Directory and others)
32 Hardware Dell infrastructure Figure 3 shows the design of the infrastructure for the Horizon Viewndashbased high IOPS type VDI
deployment that leverages Fluid Cache
An eight-node vSphere server cluster is used to host the virtual desktops Each of these server nodes has a
direct-attached PCIe SSD that is added to the Fluid Cache pool thus making each server a Fluid Cache
Provider (a server contributing to the Fluid Cache capacity) The eight PCIe SSDs were distributed among
all the servers to better balance the load on the Fluid Cache server Fluid Cache server1 These servers
were connected by using a private caching network to provide the Fluid Cache functionality Also the
servers were connected through a separate managementVDI client network and a 10 GB Ethernet iSCSI
SAN network
Another two-node vSphere server cluster is used to host the VDI infrastructure VMs such as vCenter
server View Connection server View Composer server SQL Server and Active Directory etc These
infrastructure servers were connected to the management network and the iSCSI SAN network
The Compellent storage array for the solution has two controllers and a mix of Write Intensive (WI) SSDs
15K SAS HDDs and 72K NL-SAS HDDs to provide the optimal performance and capacity needed for the
solution
Two switches are stacked together for different networks to provide redundancy in the networking layer
Ideally 40 GB Ethernet switches are recommended for the cache network While 1 GB Ethernet switches
can be used for management network it is better to use 10 GB Ethernet switches combining management
and VDI client networks The same 10 GB Ethernet switches can be used for iSCSI SAN also (with different
network traffic segmented by VLANs) provided they have adequate bandwidth needed for the specific VDI
deployment
Information about how this reference architecture was developed ensuring the optimal utilization across
the servers switches and storage arrays is discussed later in the following sections of this technical white
paper
1 Fluid Cache does not require all servers to be a Fluid Cache Provider For example in this case four
servers could have two PCIe SSDs each This configuration with four Fluid Cache Provider and four Fluid Cache Client would have had same capacity for Fluid Cache pool and all eight servers could have taken advantage of Fluid Cache However the chosen configuration for the technical white paper provides better performance the because VDI application caching load is unforming distributed among all the available servers
13 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 3 Infrastructure Set-up for VDI Solution
1 Enterprise Manager Console 2 Management and VDI Client Network 3 vSphere Servers hosting virtual desktops 4 Cache network switches (2)
5 SAN switch 6 Storage Center controllers (2) 7 Storage Center expansion enclosures (2) 8 Server hosting VDI infrastructure VMs
(Server 1) (Server 2)
14 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
4 Solution configuration This section provides information about the solution configuration and test setup for hosting Horizon View
virtual desktops including infrastructure components networking and storage subsystems
41 Host design considerations The entire VDI solution was installed in two vSphere server clusters The clusters included
Figure 4 vSphere server clusters
Infrastructure Cluster Two Dell PowerEdge R720 servers hosting VMs for Active Directory
services VMware vCenter 55 server Horizon View Connection server (primary and secondary)
View Composer server Microsoft Windows Server 2012 R2 based file server and SQL Server 2012
R2
View Client Cluster Eight Dell PowerEdge R720 servers hosting the virtual desktops Each server
had
o 2times10 core Intel Xeon CPU E5-2690v2 300GHz
o 256 GB RAM
o 1times350 GB Dell Express Flash PCIe SSD
o 1timesMellanox Connect ndash X3 card
o 1timesDual-port Broadcom NetXtreme II BCM57810 10 Gigabit NIC
o 1timesQuad-port Broadcom NetXtreme BCM5720 Gigabit NIC
Along with the other servers the above servers 40 LoginVSI launcher VMs were used to generate VDI
workload They can be hosted by two PowerEdge R720 servers or equivalent for VDI load generation
purposes
15 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
42 Network design considerations Figure 5 here shows the network layout of one of the eight PowerEdge R720 servers with vSphere 55
installed
Figure 5 vSphere host network configuration
Three network switches are used in the Fluid Cache for VDI implementation One Force10 S55 1 GB switch
for all management traffic and VDI traffic The management traffic includes hosts and vSphere
management Compellent storage management and so on The networks are segregated by using VLANs
to separate different types of traffic
One Dell Force10 S4810 10 GB switch is used for Fluid Cache cache network which supports all the traffic
between cache layer on eight VDI VM hosts Another Force10 S4810 10 GB switch is used for iSCSI
network between infrastructure hosts VDI VM hosts and Compellent SC8000
Appendix B has extended information on the vSwitch configuration for each vSphere host
16 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
43 Dell Compellent SC8000 storage array configurations The storage used to host the virtual desktops was a Dell Compellent SC8000 array running Storage Center
Operating System (SCOS) 65 All two front-end ports were 10 GB iSCSI and all two back-end ports were
six GB serial-attached SCSI (SAS) The array used two external enclosures with Write Intensive (WI) SSDs
comprising Tier 1 and 15K SAS HDDs comprising Tier 2 for performance Also 72 NL-SAS drives were
used in Tier 3 to provide capacity for user data Table 2 summarizes the storage hardware configuration
Table 2 Storage hardware components
Storage role Type Qty Description
Controllers SC8000 2 System Center Operating System (SCOS) 65
Enclosures External 2 24 bay ndash 25rdquo disk drive enclosure
Ports Ethernet ndash 10 Gbps 2 Front end host connectivity
SAS - 6 Gbps 4 Back end drive connectivity
Drives 400 GB WI SSD 12 11 active with 1 hot spare
300 GB 15K SAS HDD
21 20 active with 1 hot spare
4 TB 72K NL-SAS HDD
12 11 active with 1 hot spare
The volumes created to host the virtual desktops took advantage of the Compellent Dynamic Capacity
technology for efficient capacity allocation Table 3 lists the volume layout used for the infrastructure
functions including user data
Table 3 Volume layout for hosting infrastructure components and user data
Volume name Size Purpose
Infrastructure 500 GB Storage for Active Directory SQL Server vCenter Server View Connection Server View Composer and File Server
UserSpace 2 TB Storage for User profiles and folder redirection space (Average 25 GB per user)
Along with the infrastructure volumes the storage array also provided shared storage for hosting the
virtual desktops The volume layout used for configuring the base image (View Composer Replica) and VDI
volumes on the array is shown in Table 4
17 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 4 Dell Storage PS4210XS layout for volumes hosting virtual desktops
Volume name Size Purpose
View-Replicas1 and 2 100 GB each Storage for base image for VDI deployment
VDI-Images1 through 8 500 GB each Storage for VDI VMs in VDI Cluster Each volume hosted 100 desktops
44 vSphere host network configuration VMware vSphere 55 hypervisor was installed on all servers The network configuration on each of those
hosts is described here Each vSphere host was configured with five virtual switches vSwitch0 vSwitch1
vSwitch2 vSwitch3 and vSwitch4 to separate different types of traffic on the system
Table 5 vSwitch configuration in vSphere hosts
vSwitch Description
vSwitch0 Management Network
vSwitch1 and vSwitch2 iSCSI SAN
vSwitch3 Fluid Cache VLAN
vSwitch4 VDI LAN
For additional information about individual vSwitch configuration refer to Appendix B in the Dell technical
white paper
45 Horizon view configuration Horizon View 60 was installed by using the documentation provided by VMware
Horizon View 601 installation documentation
httpswwwvmwarecomsupportpubsview_pubshtml
Table 6 Specific configuration used in the tests
Purpose Count Type Memory CPU
Horizon View Connection Servers
2 VM 16 GB 8nos
View Composer Server 1 VM 8 GB 8nos
18 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
46 Windows 7 VM configuration Following the guidelines from VMware and Login VSI the Windows 7 base image was generated based on
a generic base VM with the following properties
VMware Virtual Hardware version 8
Two virtual CPU
3 GB RAM with 15GB reserved
25 GB virtual hard drive
One virtual NIC connected to the VDI network
Windows 7 64-bit OS
Also the base image was customized by using the VMware Horizon with View Optimization Guide for
Windows 7 and Windows 8 available at this location httpwwwvmwarecomfilespdfVMware-View-
OptimizationGuideWindows7-ENpdf
19 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
5 Horizon view test methodology This section outlines the test objectives along with the test tools and criteria used to determine the
optimal virtual desktop density and best practices for deploying Horizon View on Dell Fluid Cache for SAN
for high IOPS type VDI environment
51 Test objectives As noted in Section 11 the test objectives were
Develop an optimal end-to-end infrastructure design for a Horizon View and vSpherendashbased high
user type of VDI solution deployed by using the Fluid Cache Compellent storage PowerEdge
servers and Dell Networking switches
Determine the performance at every layer of the VDI solution stack under high IOPS workload For
example desktops generating 80ndash90 IOPSVM at steady state
Determine the performance impact of peak IO activity such as boot and login storms
52 Test tools All tests were conducted by using Login VSI 40 as the workload generator and user experience analyzer
tool Login VSI is a benchmarking tool to measure the performance and scalability of centralized desktop
environments such as Server Based Computing (SBC) and VDI
Note More information can be found at the Login VSI website httpwwwloginvsicom
In addition to Login VSI Iometer is used in desktop VMs to simulate high IOPS conditions Iometer is
invoked in desktop VMs by using custom scripting of Login VSI workloads
Note More information can be found at the Iometer project website httpwwwiometerorg
521 Load generation First the ldquoMediumrdquo workload from Login VSI was used to simulate the standard user workload The
characteristics of the Medium workload are
Up to five applications are started simultaneously
Applications include Microsoft Internet Explorer Microsoft Word Microsoft Excel Microsoft
PowerPoint PDF reader 7-Zip compression software Movie player and FreeMind
After a session is started the medium workload repeats approximately after every 48 minutes
During a loop the response time is measured after every 3ndash4 minutes
Idle time is about two minutes in each 48-minute loop
Type rate is approximately 160 milliseconds per character
After the test by using Login VSI Medium was complete tests were rerun with Login VSI Medium and
Iometer in desktop VMs to simulate high IOPS VDI workload While the Login VSI Medium generates 8ndash10
20 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
IOPSVM the latter method was able to generate 80ndash90 IOPSVM For these tests each VM in the Horizon
view pool is created with standard LoginVSI contents and applications Also Iometer is installed on each
VM After the user logs in a customized logon script starts the Iometer with required IO specification (icf
file)
522 Monitoring tools The following monitoring tools were used
Dell Compellent Enterprise Manager for monitoring Fluid Cache and Compellent SC8000 storage
array performance
VMware vCenter statistics for vSphere performance
Login VSI Analyzer for end user performance statistics
Detailed performance metrics were captured from the storage arrays hypervisors virtual desktops and
the load generators during the tests
53 Test criteria The primary focus of the tests is to validate the 800 desktop high IOPS type of VDI architecture with
acceptable user experience by using Fluid Cache for SAN VDI configurations involve many components at
different layers ndash application hypervisor server network and storage As a result multiple metrics need to
be captured at different layers to ensure that the environment is healthy and performing optimally and
appropriately for all users
The specific test criteria are described in the following sections
531 Storage capacity and IO latency The typical industry standard latency limit for storage disk IO is 10 milliseconds Maintaining this limit
ensures good user application response times when there are no other bottlenecks at the infrastructure
layer In addition Dell recommends to maintain a 10 percent spare disk space on the storage array for
optimal performance
532 System utilization at the hypervisor Even though the primary focus of these tests was storage characterization additional metrics at the
hypervisor infrastructure layer were defined to ensure solution consistency These were
CPU utilization on any vSphere server must not exceed 85 percent
Minimal memory ballooning on the VMs
Total network bandwidth utilization must not exceed 90 percent on any one link
TCPIP storage network retransmissions should be less than 05 percent
21 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
533 Virtual desktop user experience Login VSI Analyzer was also used to gather metrics on the user experience at the virtual desktop layer to
ensure that all the desktops had acceptable levels of application performance Login VSI uses the VSImax
parameter to determine the maximum number of sessions that can be obtained from a deployed solution
The calculation methodology used in VSImax is available here
httpwwwloginvsicomdocumentationindexphptitle=Analyzing_Results
534 Test configuration A single virtual desktop pool was configured by using the VMware Horizon View Administrator interface
Each pool was built from a Windows 7 base image The Windows 7 configuration information is available
in Section 46
Desktop pool properties
Automatic Desktop Pool
Users are assigned using Floating assignments
View Storage Accelerator is enabled for all hosts with a refresh period of seven days
800 desktops were deployed across eight hosts (100 desktops a host)
Replica images were stored on a separate volume
22 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
6 Test results and analysis This section presents the results from the different Horizon View VDI characterization tests and the key
findings from each test The testing was focused on the high IOPS workload profile
61 Test scenarios The following tests were conducted to gather results and analysis on the solution stack
1 Boot storm Boot storms represent the worst-case scenario where many virtual desktops are
turned on at the same time and they all contend for the system resources simultaneously This test
was used to evaluate if the storage array hosting the desktops was capable of handling huge
variation in storage IO without causing significant impact on other services
2 Login storm Login storms also represent a high IOPS situation where many users are logging in to
their virtual desktops at the beginning of a workday or a shift In this test all the desktops were
pre-booted and left in an idle state for more than 20 minutes to let their IO settle before running
the Login VSI Medium workload to simulate users logging in to their virtual desktops
3 Steady state workload for standard users with normal IOPS After the login storm for the previous
test was completed the Login VSI Medium workload was allowed to run for at least one hour to
simulate the real-world scenario of users performing their daily tasks The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
4 Steady state workload for users with high IOPS The previous test was repeated with the Login
VSI Medium workload and Iometer scripts in desktop VMs as described in Section 521 to simulate
real-world heavy users performing their daily tasks with high IOPS The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
The following sections provide results from the boot storm login storm and steady state testing for the
Fluid Cache for SAN based VDI solution
23 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
62 Boot storm IO To simulate a boot storm the virtual desktops were reset simultaneously from the VMware vSphere client
Figure 6 shows the IO pattern on the Fluid Cache for the boot storm
Figure 6 SAN HQ data showing boot storm performance with Fluid Cache array
With 800 desktops the boot storm generated about 115000 total IOPS with a majority of them being
write operations All desktops were available for use in less than four minutes
24 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
63 Login storm and steady state for standard users (LoginVSI
Medium) Login VSI was programmed to start 800 virtual desktops over a period of about 60 minutes after pre-
booting the virtual desktops The peak IOPS during the login storm observed by the vSphere servers
hosting the desktops was about 6500 IOPS (8ndash10 IOPS a VM)
In a standard user environment login storms generate significantly more write IOPS than a boot storm or
steady state because of multiple factors such as
User profile activity
Starting operating system services on the desktop
First start of applications
After a virtual desktop has achieved a steady state after user login the Windows 7 OS has cached
applications in memory and does not need to access storage each time the application is started This
leads to lesser IOPS during the steady state Figure 7 here shows the various IO characteristics during the
login storm and steady state of these tests
25 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 7 IOPS and Cache Hit for the standard user test
On the Fluid Cache layer the maximum IOPS reached 6500 with cache-hit reaching 100 percent and
read-hit around 95 percent As shown in the Figure 8 here the throughput peaked at 98 MBps with a low
latency of less than 2 msec
26 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 8 Throughput and Latency for the standard user test
631 Server host performance During the login storm and steady state of the test the vSphere host CPU memory network and storage
performance were measured on all the servers that hosted the virtual desktops The performance of one
such vSphere server is given here The other vSphere servers had similar performance characteristics
Statistics for the vSphere hosts were captured by using VMware vCenter Server The figures here show the
CPU memory and network utilization for boot storm login storm and steady state of one of the vSphere
servers hosting the virtual desktops The results shown here are for a test run with 800 no standard user
desktops in the desktop pool
27 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 9 Average CPU performance per core on one vSphere host during login storm and steady state
Figure 10 Disk space usage during login storm and steady state
0
10
20
30
40
50
60
70
80
90
100
1020 1045 1110 1135 1200 1225
Per
cen
t
Time
CPU Performance
0
50
100
150
200
250
300
1020 1040 1100 1120 1140 1200 1220
GB
Time
Memory Performance
Granted Swap used Shared common
28 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 11 Overall network performance during login storm and steady state
Figure 12 Storage adapter performance during login storm and steady state
0
10000
20000
30000
40000
50000
60000
70000
1020 1045 1110 1135 1200 1225
kBp
s
Time
Network Performance
0
05
1
15
2
25
1020 1045 1110 1135 1200 1225
mSe
c
Time
Storage adaptor performance
29 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
The key observations from the statistics were
CPU utilization was less than the 85 percent threshold throughout the test
Active disk space usage was about 80 percent during the boost storm and about 60 percent
during login storm and steady state There was minimal-or no memory ballooning observed
Network utilization was about 45 percent which included all the networks such as iSCSI SAN VDI
LAN Management LAN and vMotion LAN
Average read- and write latencies at the storage adapter level were very close to the observed
latencies in Fluid Cache 2 msec
632 Monitoring user experience Figure 13 here shows the response time as experienced by each user as calculated by Login VSI The graph
clearly shows that the VSImax (Dynamic) value has not been reached and there were non-responsive or
inactive sessions This means that the array is capable of supporting the 1000 desktops and all users have
acceptable response times for applications that the user is has started
Figure 13 Login VSI user experience monitoring for 800 standard user desktops
30 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
633 Standard user test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SANndashbased VDI solution is able to host 800 virtual desktops and support
a standard user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only operations and
less than 2 percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to handle this login storm easily with low latency mdash it delivered the required 6500 IOPS with less
than 2 milliseconds of write latency with a 99 percent write VDI IO workload
64 Login storm and steady state with high IOPS (LoginVSI Medium +
Iometer) As mentioned earlier Iometer was used in desktop VMs alongside the Login VSI Medium workload to
simulate high IOPS type of VDI environment To mimic actual VDI workload profile the following Iometer
profile was used
20 KB block size 80 percent write 75 percent random with 25 msec burst delay
Figure 14 here shows the various IO characteristics during the login storm and steady state of these tests
Figure 14 IOPS and Cache Hit for the high IOPS test
On the Fluid Cache layer the maximum IOPS reached was approximately 72000 (or 90 IOPSVM) with
cache write-hit 100 percent and read-hit around 95 percent As shown in the Figure 15 the throughput
peaked at greater than 900 MBps with a peak latency of approximately 75 msec
31 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 15 Throughput and Latency for the high IOPS test
32 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
641 Server host performance Similar to the standard user test statistics for the vSphere hosts were captured by using VMware vCenter
Server during the high IOPS (heavy user) test also There are no significant differences in CPU disk space
and network utilization between standard users and heavy users The storage adapter latency is also
showing similar on hosts and observed on Fluid Cache
642 User experience monitoring Figure 16 here shows the response time as experienced by each user as calculated by Login VSI for the
heavy user test The graph shows that the VSImax (Dynamic) value was 796 indicating that the solution is
capable of supporting the 800 user high IOPS desktops with 90 IOPSVM
Figure 16 Login VSI user experience monitoring for 800 user high IOPS desktops
33 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
643 High IOPS (heavy user) test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SAN based VDI solution is able to host 800 virtual desktops and support a
high user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only and less than 2
percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to easily handle this login storm with low latency Subsequently it was able to handle 72000 IOPS
at high IOPS steady state with 90 IOPSVM with a maximum of 75 msec latency
34 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
7 Best practices This section provides the best practices derived from the testing and analysis in Section 6
71 Virtual Desktop Infrastructure This section provides best practices for the implementation of VDI using Dell Fluid Cache for SAN
711 Implement roaming profiles and folder redirection Dell recommends that all users in the VDI environment be configured with roaming profiles and folder
redirection This preserves user profiles and user data across boots while using non-persistent virtual
desktops
Also Dell recommends to use a high performance file service to provide the profile and folder redirection
A separate array may be used to host these volumes for best performance
712 Boot and login storm considerations Section 62 demonstrated the Fluid Cache for SAN performance under boot storm To avoid any potential
IO bursts because of boot storm and degraded user experience and performances Dell recommends that
all or portion of desktops be prebooted Connection brokers such as VMware Horizon View provide the
functionality to configure number of standby desktops
713 Windows 7 master image for desktop VMs Dell recommends that the operating system be customized in order to provide the best performance in a
VDI environment This includes disabling some services which may not be required This can improve
performance for the end user VMware has a specific set of recommendations and settings for Windows 7
and Windows 8 that allow for faster logins quicker screen refreshes and generally better performance
The VMware recommendations for Windows 7 and Windows 8 image optimization can be found here
httpwwwvmwarecomresourcestechresources10157
714 VDI Management infrastructure recommendations Dell recommends to have redundancy and load balancing for all VDI management services in the case of
VMware Horizon View solution as tested here the vSphere Server VMware Horizon View Servers and SQL
Servers Ideally these should be running on clustered hosts with VMware vSphere DRS (distributed
resource scheduler) and HA (high availability) enabled
72 Server host The vSphere servers hosting the infrastructure service providers and the virtual desktops are
recommended to be configured as follows
35 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Follow VMware and Dell best practices for installing and configuring vSphere
Separate virtual switches to segregate iSCSI SAN traffic VDI traffic vMotion traffic and Management
network traffic
Each network path must be assigned to a minimum of two physical NICs for high availability
VMware Knowledge Base article about best practices for installing vSphere 55
httpkbvmwarecomkb2052329
73 Network layer Dell recommends that at least two physical NICs on each vSphere server be dedicated to the VDI network
Use VLANs to segregate different types of network traffic on the same physical network In this case Dell
recommends to separate the infrastructure vMotion and VDI LAN traffic in to separate VLANs
Do not use VLANs to segregate iSCSI SAN and Fluide Cache traffic It is required that SAN and Cache traffic
be on separate dedicated physical network to provide the best performance
Virtual switches in vSphere have a default limit of 120 ports If the number of virtual desktops on each host
exceeds the available ports vSwitch properties should be changed to support the required number of
virtual desktops This change requires a restart of the host vSphere server
On iSCSI SAN switches Spanning tree must be disabled on switch ports connected to end devices for
server and storage ports The PortFast setting must be enabled in the switch configuration for these ports
Jumbo frames and Flow control (if the NICs support it) should be enabled for all components of the iSCSI
network
More information about configuring Dell Networking switches for use with Dell Storage iSCSI SANs is
available here
httpencommunitydellcomtechcenterstoragewwiki4250switch-configuration-guides-by-sisaspx
74 Storage The Dell SC storage arrays combined with Fluid Cache is an excellent platform for providing cost-effective
performance in VDI environments
Fluid Cache for SAN extends the power of Compellent intelligent data placement from the SAN to the
server By providing a single infrastructure for data at both high- and low ends of the performance
spectrum Fluid Cache for SAN with Storage Center 65 array software eliminates the tradeoffs between
server performance and full-featured SAN benefits such as reliability manageability and data protection
Dell recommends to have separate volumes for base image and virtual desktops This enables better
manageability of the volumes easier performance monitoring and allows easy future growth
Dell recommends to use a separate high performance file service to provide file shares for roaming
profiles and user shares
36 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
8 Conclusion The technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed by using a Horizon View VDI platform leveraging Dell Fluid Cache for SAN The storage IO
characteristics under various VDI workload scenarios (boot storm login storm and steady state) along
with performance characteristics throughout the VDI stack (for example vSphere server performance and
user experience) demonstrate the optimal configuration of the infrastructure used for this VDI
deployment For more information about Fluid Cache contact your Dell account manager
37 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
A Horizon view solution configuration
Table 7 Hardware components
Hardware components Description
Virtual Desktops 4 timesDell PowerEdge R720 Servers (Fluid Cache Providers)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
2times350 GB Dell Express Flash PCIe SSDs
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
4 x Dell PowerEdge R720 Servers (Fluid Cache Clients)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55 U2 on all R720 servers Windows 7 (64 Bit) VMs
Infrastructure Servers 2 x Dell PowerEdge R720 servers
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
96 GB RAM
2times300 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55U2 on all R720 servers VMs are loaded with Microsoft Windows 2008 R2
Active Directory
VMware Horizon View 60 Server 1
VMware Horizon View 60 Server 2
VMware vCenter Server 55 update 2
VMware Horizon View Composer
SQL Server
File Server
Login VSI Launchers 8 x Dell PowerEdge M610 servers
2timesIntelreg Xeonreg E-5503 200 GHz Processors
16 GB RAM
4times146 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57711 10GbE NIC
ESXi 51 installed on all R810 servers VMs are loaded with Microsoft Windows 7 64bit Each VM supports up to 30 Login VSI launcher sessions
38 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Network Management VDI LAN
1timesDell Force10 S55 1Gb Ethernet Switch
iSCSI SAN
1timesDell Force10 S4810 10Gb Ethernet Switch
Cache network
1timesDell Force10 S4810 10Gb Ethernet Switch
One Force10 S4810 switch might suffice for all the cache iSCSI SAN VDI LAN and management traffic
Storage 2timesDell Compellent SC8000 controllers 4times6Gb SAS 4-port PCI-E Full-height cards for back-end connectivity 2times10Gb iSCSI 2 port PCI-E Low-profile IO cards for front end connectivity 1timesDell Compellent SC200 disk enclosures 12times4TB NL-SAS 6Gb 72K 35rdquo drives
User Data Infrastructure VMs Virtual Desktops
Performance Monitoring
Dell Compellent Enterprise Manager Dell Fluid Cache for SAN performance monitoring tool () vCenter Performance monitoring Liquidware Stratusphere UX
Performance monitoring on Compellent arrays Fluid Cache performance monitoring Performance monitoring and capture at the ESXi host User experience monitoring on the virtual desktop
39 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 8 Software components
Software components Description Version
Dell Fluid Cache for SAN 20
Dell Compellent Storage Center 64
Dell Compellent Enterprise Manager 64
VMware Horizon View Server 60
VMware Horizon View Composer 60
VMware Horizon View Agent 60
VMware Horizon View Client 64-bit 60
VMware ESXi Hypervisor 55 U2
VMware vCenter Server 55 U2
Microsoft SQL Server 2008R2 Enterprise x64 105016001
Client VM OS Microsoft Windows 7 Enterprise x64 SP1
Management VM OS Microsoft Windows Server 2008 Enterprise R2 x64 SP1
Microsoft Office MS office 2010 Standard Service Pack 1
Login VSI Version 40
Iometer 20060727
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
3 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Contents Revisions 2
Executive summary 5
1 Introduction 6
11 Objectives 6
111 Audience 6
2 Dell Fluid Cache for SAN and VDI 7
3 Solution architecture 9
31 Software Horizon view 9
311 Horizon view components 10
312 Virtual desktops 10
313 Horizon view desktop pools 11
314 Using linked clones 11
315 Hypervisor platform VMware vSphere 55 11
32 Hardware Dell infrastructure 12
4 Solution configuration 14
41 Host design considerations 14
42 Network design considerations 15
43 Dell Compellent SC8000 storage array configurations 16
44 vSphere host network configuration 17
45 Horizon view configuration 17
46 Windows 7 VM configuration 18
5 Horizon view test methodology 19
51 Test objectives 19
52 Test tools 19
521 Load generation 19
522 Monitoring tools 20
53 Test criteria 20
531 Storage capacity and IO latency 20
532 System utilization at the hypervisor 20
533 Virtual desktop user experience 21
534 Test configuration 21
4 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
6 Test results and analysis 22
61 Test scenarios 22
62 Boot storm IO 23
63 Login storm and steady state for standard users (LoginVSI Medium) 24
631 Server host performance 26
632 Monitoring user experience 29
633 Standard user test results summary 30
64 Login storm and steady state for heavy users (LoginVSI Medium + Iometer) 30
641 Server host performance 32
642 User experience monitoring 32
643 Heavy user test results summary 33
7 Best practices 34
71 Virtual Desktop Infrastructure 34
711 Implement roaming profiles and folder redirection 34
712 Boot and login storm considerations 34
713 Windows 7 master image for desktop VMs 34
714 VDI Management infrastructure recommendations 34
72 Server host 34
73 Network layer 35
74 Storage 35
8 Conclusion 36
A Horizon view solution configuration 37
B vSphere host network configuration 40
B1 vSwitch ndash Management traffic 40
B2 vSwitch - iSCSI 40
B3 vSwitch ndash Fluid Cache network 41
B4 vSwitch3 41
Additional resources 42
Acknowledgements 43
Feedback 43
5 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Executive summary
A Virtual Desktop Infrastructure (VDI) deployment can place high storage capacity and performance
demands on the storage platform For example consolidating large amounts of inexpensive stand-alone
desktop storage in to a centralized infrastructure can create tremendous storage capacity demands on
centrally managed shared storage used in VDI deployments Performance demands are determined by
the number of IO operations per second (IOPS) generated by basic desktop client operations such as
system boot logon and logoff and by desktop usage operations from different users Storm events such
as simultaneous booting of many desktops morning logons and afternoon logoffs by many users at
approximately the same time and virus scan can cause IO requirement variances that place high
performance demands on the storage infrastructure
Current VDI solutions in the market can cost-effectively manage desktop virtualization use cases where
performance demands are not really demanding For example a task worker environment in a call center
can generate 5ndash10 IOPSVM or a knowledge worker environment in an office can generate 15ndash25
IOPSVM Typically hybrid arrays or all-flash arrays are deployed to accommodate performance needs in
these VDI environments
The next frontier for VDI to conquer is the high IOPS use cases such as a software developer organization
or an engineering CADCAM team In these use cases not only the capacity demands are large
(repositories for code or design in development) but also performance demands are extremely high
(often 50ndash80 IOPSVM)
Dell Fluid Cache for SAN mdashan innovative server-side readwrite caching solution for workload
acceleration can provide an innovative cost-effective solution for high IOPS type VDI environments
Even though these VDI environments need a lot of storage capacity the working set is typically relatively
small However this working set is very IO intensivemdashmore read operations (write operations) during
boot storms and more write-operations during steady state Fluid Cache software can provide extremely
high IOPS with minimal latency for these working set VDI data leveraging PCIe SSDs as readwrite cache
pool in the computational tier while a Dell Compellent SAN storage array can provide the performance
and large capacity needed for the shared storage This combination fits perfectly for high IOPS VDI
environment
This technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed in a VMware Horizon View VDI infrastructure leveraging Fluid Cache and Compellent storage
array The test infrastructure also included Dell Networking switches and Dell PowerEdge servers running
VMware vSphere 55 as the hypervisor In the test environment the solution infrastructure successfully
hosted 800 desktops with satisfactory performance results across all layers of the stack including the
user layer hypervisor layer and storage layer while delivering approximately 90 IOPSVM as a sustained
steady state load Fluid Cache performance ensured excellent end-user desktop application response
times as determined by the user-level experience monitoring software LoginVSIrsquos VSIMax Details are
provided for the storage IO characteristics about various VDI workload scenarios such as boot and login
storms along with performance characteristics throughout the VDI stack
6 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
1 Introduction Desktop virtualization platforms such as VMware Horizon View 60 (Horizon View) can provide
organizations with significant cost savings streamlined implementation and ease of desktop
management In order to achieve these VDI benefits and to ensure optimal user experience the end-to-
end infrastructure design and sizing considerations need to be addressed carefully While VDI workloads
for task and knowledge workers are correctly understood by using many cost-effective solutions that are
available the high IOPS 800-user VDI use cases are addressed less often because current solutions
typically do not meet the stringent performance- and capacity requirements of these use cases in an
economically sensible manner
The goal of this technical white paper is to present the results of a series of storage IO performance tests
and provide the optimal end-to-end infrastructure design for high IOPS 800-user type VDI environments
leveraging Dell Fluid Cache for SAN Dell Compellent SAN storage arrays Dell PowerEdge servers and Dell
Networking switches
11 Objectives The primary objectives of the tests conducted for this technical white paper are
Develop an optimal end-to-end infrastructure design for a Horizon View and vSphere-based
heavy user type VDI solution deployed by using the Fluid Cache Compellent storage PowerEdge
servers and Dell Networking switches
Determine the performance at every layer of the VDI solution stack under high IOPS workload For
example desktops generating 80ndash90 IOPSVM at steady state
Determine the performance impact of peak IO activity such as boot and login storms
The test infrastructure used for the tests included
VMware Horizon View 60
VMware vSphere 55 hypervisor
Dell PowerEdge R720 servers with Dell Express PCIe SSDs
Dell Networking S4810 switches
Dell Compellent SC8000 storage array
111 Audience This technical white paper is intended for solution architects storage network engineers system
administrators and IT managers who need to understand about designing properly sizing and deploying
Horizon View-based VDI solutions by using Dell infra design properly sizing and deploying Horizon View-
based VDI solutions by using Dell infrastructure It is expected that the reader has a working knowledge of
the Horizon View architecture vSphere system administration iSCSI SAN network design and Dell
Compellent SAN operation
7 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
2 Dell Fluid Cache for SAN and VDI Dell Fluid Cache for SAN utilizes direct-attached Dell PowerEdge Express Flash NVMe PCIe SSDs and
remote direct memory access (RDMA) networking capabilities to create a clustered caching pool for
improved storage workload performance Applications write directly to the cache pool the
acknowledgement is sent back to the application and in the background the IO is flushed to the external
storage array Data is copied in to the cache pool when it is accessed (read) by application and is available
from the cache pool for reread operations Also data that is written into the cache pool by the application
is then available for reread operations from the application A high-speed link to other cache nodes in the
Fluid Cache for SAN pool allows the data to remain highly available by replicating blocks of data even if a
single node in cache pool stops working Fluid Cache for SAN provides a single management interface and
provides other capabilities such as cache-aware snapshots and replication and compression
Figure 1 shows an example environment highlighting how Fluid Cache for SAN communicates between
server and storage Three nodes are required to run Dell Fluid Cache for SAN software Two of these three
nodes are required to have a minimum of one Dell PowerEdge Express Flash NVMe PCIe SSD each and
the network for private cache network is based on the low-latency RDMA protocol The RDMA network
handles the cache pool communication between the nodes Creation and management of the Fluid
Cache cluster are accomplished by using the Dell Compellent Enterprise Manager software through
automatic cache server discovery
Figure 1 Dell Fluid Cache for SAN communication
8 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Fluid Cache for SAN is an ideal solution for high IOPS type VDI environment with highly write-intensive
workloads because it provides extremely fast and low-latency server-side write back caching Because
writes are mirrored across high-speed network and later destaged to the SAN with significant write
coalescing this solution can sustain significantly higher IOPSVM than an external hybrid or all-flash array
ndashbased solution could
9 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
3 Solution architecture The overall architecture of the VDI solution for the high IOPS environment is shown in the figure here
Figure 2 VDI solution architecture
31 Software Horizon view Horizon View is a VDI solution that includes a complete suite of tools for delivering desktops as a secure
and managed service from a centralized infrastructure A Horizon View infrastructure consists of many
different software network and hardware layer components This section presents an overview of the key
Horizon View components and technologies that are critical for successful design and deployment of the
VDI environment
10 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
311 Horizon view components A functional list of Horizon View components used in this solution is given in the table here
Table 1 Horizon View components
Component Description
Client Devices Personal computing devices used by end users to run the Horizon View Client These can include special end-point devices such as Dell Wyse end points mobile phones and PCs
Horizon View Connection Server
A software service that acts as a broker for client connections by authenticating and then directing the incoming user requests to the appropriate virtual desktop physical desktop or terminal server
Horizon View Client Software that is used to access the Horizon View desktops
Horizon View Agent A service that runs on all systems used as sources for Horizon View desktops and facilitates network communication between the Horizon View clients and the Horizon View server
Horizon View Administrator
A web-based administration platform for the Horizon View infrastructure components
vCenterreg Server Central administration platform for configuring provisioning and managing VMware virtualized data centers
Horizon View Composer
A service running with Horizon View servers used to create pools of virtual desktops from a shared-base image to reduce storage capacity requirements
312 Virtual desktops Virtual desktops can be classified in to two major categories persistent and non-persistent
Persistent desktop environment All configuration and personalization on the assigned desktop is kept for
the user-between sessions When using persistent desktops an administrator usually has to provision
additional storage along with other administrative requirements such as patching and upgrading of
individual desktops
Non-persistent desktop environment Users are dynamically assigned virtual desktop VMs from a pool of
resources during login This type of virtual desktop does not retain any information between sessions At
logoff all changes are simply discarded and the virtual desktop is returned to the original state Patching
and upgrading non-persistent desktops requires only making the change to the base image and refreshing
or recomposing the virtual desktop pool Thus these desktops are much easier to manage but lack the
potential for persistent user customization
11 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
313 Horizon view desktop pools A desktop pool is a term VMware uses to describe a collection of desktops that are managed as a single
entity by the Horizon View Administrator interface Horizon View desktop pools allow administrators to
group users depending on the type of service the user requires There are two types of pools ndash Automated
and Manual
In Horizon View an Automated Pool is a collection of VMs cloned from a base template while a Manual
pool is created by the Horizon View Manager from existing desktop sources physical or virtual For each
desktop in the Manual pool the administrator selects a desktop source to deliver Horizon View access to
the clients
VMware View Personas profile management features can be used to achieve persistent desktop-like
behavior on non-persistent desktops By using these features an administrator can design a user account
where the configuration settings are written to a remote profile that is stored separately from the virtual
desktop image files This reduces the need for additional management on individual virtual desktops while
still providing a customized user experience
314 Using linked clones Significant storage space savings and increased efficiencies in desktop VM provisioning and administration
are possible when using VMware-linked clones A linked clone is a duplicate VM that shares the same base
image with the original VM but has separate differential data disks to track the differences from the
original one Each linked clone functions as an independent desktop VM with its own unique identity
Because linked clones share the same base image they consume significantly less storage disk space than
a set of completely independent VM images Temporary system data and other data unique to each linked
clone desktop VM are written to separate differential data storage and these temporary changes are
discarded during restart andor user logoff Persistent data such as user profiles applications and user
data can be optionally redirected to a CIFS share With this model software maintenance updates
antivirus remediation and patches need to be applied only on the base image These base image changes
automatically take effect on all linked clones without affecting any user settings and data
To configure linked clones the administrator creates a snapshot of a parent VM image with the required
OS settings and software installed Horizon View Composer first creates a full replica (clone) of the parent
VM and then uses this replica to create linked clones The replica can be placed on the same data store as
the linked clones or on a separate data store
More information about configuring linked clones can be found in the ldquoCreating Desktop Poolsrdquo section of
the VMware Horizon View Online Library here
315 Hypervisor platform VMware vSphere 55 VMware vSphere 55 is the enterprise virtualization platform used for building VDI and cloud
infrastructures VMware vSphere 55 includes three major layers virtualization management and interface
The virtualization layer includes infrastructure and application services The management layer is central
12 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
for configuring provisioning and managing virtualized environments The interface layer includes the
vSphere client and the vSphere web client
Throughout the solution all VMware and Microsoft best practices and prerequisites for core services were
used (NTP DNS Active Directory and others)
32 Hardware Dell infrastructure Figure 3 shows the design of the infrastructure for the Horizon Viewndashbased high IOPS type VDI
deployment that leverages Fluid Cache
An eight-node vSphere server cluster is used to host the virtual desktops Each of these server nodes has a
direct-attached PCIe SSD that is added to the Fluid Cache pool thus making each server a Fluid Cache
Provider (a server contributing to the Fluid Cache capacity) The eight PCIe SSDs were distributed among
all the servers to better balance the load on the Fluid Cache server Fluid Cache server1 These servers
were connected by using a private caching network to provide the Fluid Cache functionality Also the
servers were connected through a separate managementVDI client network and a 10 GB Ethernet iSCSI
SAN network
Another two-node vSphere server cluster is used to host the VDI infrastructure VMs such as vCenter
server View Connection server View Composer server SQL Server and Active Directory etc These
infrastructure servers were connected to the management network and the iSCSI SAN network
The Compellent storage array for the solution has two controllers and a mix of Write Intensive (WI) SSDs
15K SAS HDDs and 72K NL-SAS HDDs to provide the optimal performance and capacity needed for the
solution
Two switches are stacked together for different networks to provide redundancy in the networking layer
Ideally 40 GB Ethernet switches are recommended for the cache network While 1 GB Ethernet switches
can be used for management network it is better to use 10 GB Ethernet switches combining management
and VDI client networks The same 10 GB Ethernet switches can be used for iSCSI SAN also (with different
network traffic segmented by VLANs) provided they have adequate bandwidth needed for the specific VDI
deployment
Information about how this reference architecture was developed ensuring the optimal utilization across
the servers switches and storage arrays is discussed later in the following sections of this technical white
paper
1 Fluid Cache does not require all servers to be a Fluid Cache Provider For example in this case four
servers could have two PCIe SSDs each This configuration with four Fluid Cache Provider and four Fluid Cache Client would have had same capacity for Fluid Cache pool and all eight servers could have taken advantage of Fluid Cache However the chosen configuration for the technical white paper provides better performance the because VDI application caching load is unforming distributed among all the available servers
13 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 3 Infrastructure Set-up for VDI Solution
1 Enterprise Manager Console 2 Management and VDI Client Network 3 vSphere Servers hosting virtual desktops 4 Cache network switches (2)
5 SAN switch 6 Storage Center controllers (2) 7 Storage Center expansion enclosures (2) 8 Server hosting VDI infrastructure VMs
(Server 1) (Server 2)
14 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
4 Solution configuration This section provides information about the solution configuration and test setup for hosting Horizon View
virtual desktops including infrastructure components networking and storage subsystems
41 Host design considerations The entire VDI solution was installed in two vSphere server clusters The clusters included
Figure 4 vSphere server clusters
Infrastructure Cluster Two Dell PowerEdge R720 servers hosting VMs for Active Directory
services VMware vCenter 55 server Horizon View Connection server (primary and secondary)
View Composer server Microsoft Windows Server 2012 R2 based file server and SQL Server 2012
R2
View Client Cluster Eight Dell PowerEdge R720 servers hosting the virtual desktops Each server
had
o 2times10 core Intel Xeon CPU E5-2690v2 300GHz
o 256 GB RAM
o 1times350 GB Dell Express Flash PCIe SSD
o 1timesMellanox Connect ndash X3 card
o 1timesDual-port Broadcom NetXtreme II BCM57810 10 Gigabit NIC
o 1timesQuad-port Broadcom NetXtreme BCM5720 Gigabit NIC
Along with the other servers the above servers 40 LoginVSI launcher VMs were used to generate VDI
workload They can be hosted by two PowerEdge R720 servers or equivalent for VDI load generation
purposes
15 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
42 Network design considerations Figure 5 here shows the network layout of one of the eight PowerEdge R720 servers with vSphere 55
installed
Figure 5 vSphere host network configuration
Three network switches are used in the Fluid Cache for VDI implementation One Force10 S55 1 GB switch
for all management traffic and VDI traffic The management traffic includes hosts and vSphere
management Compellent storage management and so on The networks are segregated by using VLANs
to separate different types of traffic
One Dell Force10 S4810 10 GB switch is used for Fluid Cache cache network which supports all the traffic
between cache layer on eight VDI VM hosts Another Force10 S4810 10 GB switch is used for iSCSI
network between infrastructure hosts VDI VM hosts and Compellent SC8000
Appendix B has extended information on the vSwitch configuration for each vSphere host
16 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
43 Dell Compellent SC8000 storage array configurations The storage used to host the virtual desktops was a Dell Compellent SC8000 array running Storage Center
Operating System (SCOS) 65 All two front-end ports were 10 GB iSCSI and all two back-end ports were
six GB serial-attached SCSI (SAS) The array used two external enclosures with Write Intensive (WI) SSDs
comprising Tier 1 and 15K SAS HDDs comprising Tier 2 for performance Also 72 NL-SAS drives were
used in Tier 3 to provide capacity for user data Table 2 summarizes the storage hardware configuration
Table 2 Storage hardware components
Storage role Type Qty Description
Controllers SC8000 2 System Center Operating System (SCOS) 65
Enclosures External 2 24 bay ndash 25rdquo disk drive enclosure
Ports Ethernet ndash 10 Gbps 2 Front end host connectivity
SAS - 6 Gbps 4 Back end drive connectivity
Drives 400 GB WI SSD 12 11 active with 1 hot spare
300 GB 15K SAS HDD
21 20 active with 1 hot spare
4 TB 72K NL-SAS HDD
12 11 active with 1 hot spare
The volumes created to host the virtual desktops took advantage of the Compellent Dynamic Capacity
technology for efficient capacity allocation Table 3 lists the volume layout used for the infrastructure
functions including user data
Table 3 Volume layout for hosting infrastructure components and user data
Volume name Size Purpose
Infrastructure 500 GB Storage for Active Directory SQL Server vCenter Server View Connection Server View Composer and File Server
UserSpace 2 TB Storage for User profiles and folder redirection space (Average 25 GB per user)
Along with the infrastructure volumes the storage array also provided shared storage for hosting the
virtual desktops The volume layout used for configuring the base image (View Composer Replica) and VDI
volumes on the array is shown in Table 4
17 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 4 Dell Storage PS4210XS layout for volumes hosting virtual desktops
Volume name Size Purpose
View-Replicas1 and 2 100 GB each Storage for base image for VDI deployment
VDI-Images1 through 8 500 GB each Storage for VDI VMs in VDI Cluster Each volume hosted 100 desktops
44 vSphere host network configuration VMware vSphere 55 hypervisor was installed on all servers The network configuration on each of those
hosts is described here Each vSphere host was configured with five virtual switches vSwitch0 vSwitch1
vSwitch2 vSwitch3 and vSwitch4 to separate different types of traffic on the system
Table 5 vSwitch configuration in vSphere hosts
vSwitch Description
vSwitch0 Management Network
vSwitch1 and vSwitch2 iSCSI SAN
vSwitch3 Fluid Cache VLAN
vSwitch4 VDI LAN
For additional information about individual vSwitch configuration refer to Appendix B in the Dell technical
white paper
45 Horizon view configuration Horizon View 60 was installed by using the documentation provided by VMware
Horizon View 601 installation documentation
httpswwwvmwarecomsupportpubsview_pubshtml
Table 6 Specific configuration used in the tests
Purpose Count Type Memory CPU
Horizon View Connection Servers
2 VM 16 GB 8nos
View Composer Server 1 VM 8 GB 8nos
18 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
46 Windows 7 VM configuration Following the guidelines from VMware and Login VSI the Windows 7 base image was generated based on
a generic base VM with the following properties
VMware Virtual Hardware version 8
Two virtual CPU
3 GB RAM with 15GB reserved
25 GB virtual hard drive
One virtual NIC connected to the VDI network
Windows 7 64-bit OS
Also the base image was customized by using the VMware Horizon with View Optimization Guide for
Windows 7 and Windows 8 available at this location httpwwwvmwarecomfilespdfVMware-View-
OptimizationGuideWindows7-ENpdf
19 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
5 Horizon view test methodology This section outlines the test objectives along with the test tools and criteria used to determine the
optimal virtual desktop density and best practices for deploying Horizon View on Dell Fluid Cache for SAN
for high IOPS type VDI environment
51 Test objectives As noted in Section 11 the test objectives were
Develop an optimal end-to-end infrastructure design for a Horizon View and vSpherendashbased high
user type of VDI solution deployed by using the Fluid Cache Compellent storage PowerEdge
servers and Dell Networking switches
Determine the performance at every layer of the VDI solution stack under high IOPS workload For
example desktops generating 80ndash90 IOPSVM at steady state
Determine the performance impact of peak IO activity such as boot and login storms
52 Test tools All tests were conducted by using Login VSI 40 as the workload generator and user experience analyzer
tool Login VSI is a benchmarking tool to measure the performance and scalability of centralized desktop
environments such as Server Based Computing (SBC) and VDI
Note More information can be found at the Login VSI website httpwwwloginvsicom
In addition to Login VSI Iometer is used in desktop VMs to simulate high IOPS conditions Iometer is
invoked in desktop VMs by using custom scripting of Login VSI workloads
Note More information can be found at the Iometer project website httpwwwiometerorg
521 Load generation First the ldquoMediumrdquo workload from Login VSI was used to simulate the standard user workload The
characteristics of the Medium workload are
Up to five applications are started simultaneously
Applications include Microsoft Internet Explorer Microsoft Word Microsoft Excel Microsoft
PowerPoint PDF reader 7-Zip compression software Movie player and FreeMind
After a session is started the medium workload repeats approximately after every 48 minutes
During a loop the response time is measured after every 3ndash4 minutes
Idle time is about two minutes in each 48-minute loop
Type rate is approximately 160 milliseconds per character
After the test by using Login VSI Medium was complete tests were rerun with Login VSI Medium and
Iometer in desktop VMs to simulate high IOPS VDI workload While the Login VSI Medium generates 8ndash10
20 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
IOPSVM the latter method was able to generate 80ndash90 IOPSVM For these tests each VM in the Horizon
view pool is created with standard LoginVSI contents and applications Also Iometer is installed on each
VM After the user logs in a customized logon script starts the Iometer with required IO specification (icf
file)
522 Monitoring tools The following monitoring tools were used
Dell Compellent Enterprise Manager for monitoring Fluid Cache and Compellent SC8000 storage
array performance
VMware vCenter statistics for vSphere performance
Login VSI Analyzer for end user performance statistics
Detailed performance metrics were captured from the storage arrays hypervisors virtual desktops and
the load generators during the tests
53 Test criteria The primary focus of the tests is to validate the 800 desktop high IOPS type of VDI architecture with
acceptable user experience by using Fluid Cache for SAN VDI configurations involve many components at
different layers ndash application hypervisor server network and storage As a result multiple metrics need to
be captured at different layers to ensure that the environment is healthy and performing optimally and
appropriately for all users
The specific test criteria are described in the following sections
531 Storage capacity and IO latency The typical industry standard latency limit for storage disk IO is 10 milliseconds Maintaining this limit
ensures good user application response times when there are no other bottlenecks at the infrastructure
layer In addition Dell recommends to maintain a 10 percent spare disk space on the storage array for
optimal performance
532 System utilization at the hypervisor Even though the primary focus of these tests was storage characterization additional metrics at the
hypervisor infrastructure layer were defined to ensure solution consistency These were
CPU utilization on any vSphere server must not exceed 85 percent
Minimal memory ballooning on the VMs
Total network bandwidth utilization must not exceed 90 percent on any one link
TCPIP storage network retransmissions should be less than 05 percent
21 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
533 Virtual desktop user experience Login VSI Analyzer was also used to gather metrics on the user experience at the virtual desktop layer to
ensure that all the desktops had acceptable levels of application performance Login VSI uses the VSImax
parameter to determine the maximum number of sessions that can be obtained from a deployed solution
The calculation methodology used in VSImax is available here
httpwwwloginvsicomdocumentationindexphptitle=Analyzing_Results
534 Test configuration A single virtual desktop pool was configured by using the VMware Horizon View Administrator interface
Each pool was built from a Windows 7 base image The Windows 7 configuration information is available
in Section 46
Desktop pool properties
Automatic Desktop Pool
Users are assigned using Floating assignments
View Storage Accelerator is enabled for all hosts with a refresh period of seven days
800 desktops were deployed across eight hosts (100 desktops a host)
Replica images were stored on a separate volume
22 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
6 Test results and analysis This section presents the results from the different Horizon View VDI characterization tests and the key
findings from each test The testing was focused on the high IOPS workload profile
61 Test scenarios The following tests were conducted to gather results and analysis on the solution stack
1 Boot storm Boot storms represent the worst-case scenario where many virtual desktops are
turned on at the same time and they all contend for the system resources simultaneously This test
was used to evaluate if the storage array hosting the desktops was capable of handling huge
variation in storage IO without causing significant impact on other services
2 Login storm Login storms also represent a high IOPS situation where many users are logging in to
their virtual desktops at the beginning of a workday or a shift In this test all the desktops were
pre-booted and left in an idle state for more than 20 minutes to let their IO settle before running
the Login VSI Medium workload to simulate users logging in to their virtual desktops
3 Steady state workload for standard users with normal IOPS After the login storm for the previous
test was completed the Login VSI Medium workload was allowed to run for at least one hour to
simulate the real-world scenario of users performing their daily tasks The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
4 Steady state workload for users with high IOPS The previous test was repeated with the Login
VSI Medium workload and Iometer scripts in desktop VMs as described in Section 521 to simulate
real-world heavy users performing their daily tasks with high IOPS The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
The following sections provide results from the boot storm login storm and steady state testing for the
Fluid Cache for SAN based VDI solution
23 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
62 Boot storm IO To simulate a boot storm the virtual desktops were reset simultaneously from the VMware vSphere client
Figure 6 shows the IO pattern on the Fluid Cache for the boot storm
Figure 6 SAN HQ data showing boot storm performance with Fluid Cache array
With 800 desktops the boot storm generated about 115000 total IOPS with a majority of them being
write operations All desktops were available for use in less than four minutes
24 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
63 Login storm and steady state for standard users (LoginVSI
Medium) Login VSI was programmed to start 800 virtual desktops over a period of about 60 minutes after pre-
booting the virtual desktops The peak IOPS during the login storm observed by the vSphere servers
hosting the desktops was about 6500 IOPS (8ndash10 IOPS a VM)
In a standard user environment login storms generate significantly more write IOPS than a boot storm or
steady state because of multiple factors such as
User profile activity
Starting operating system services on the desktop
First start of applications
After a virtual desktop has achieved a steady state after user login the Windows 7 OS has cached
applications in memory and does not need to access storage each time the application is started This
leads to lesser IOPS during the steady state Figure 7 here shows the various IO characteristics during the
login storm and steady state of these tests
25 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 7 IOPS and Cache Hit for the standard user test
On the Fluid Cache layer the maximum IOPS reached 6500 with cache-hit reaching 100 percent and
read-hit around 95 percent As shown in the Figure 8 here the throughput peaked at 98 MBps with a low
latency of less than 2 msec
26 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 8 Throughput and Latency for the standard user test
631 Server host performance During the login storm and steady state of the test the vSphere host CPU memory network and storage
performance were measured on all the servers that hosted the virtual desktops The performance of one
such vSphere server is given here The other vSphere servers had similar performance characteristics
Statistics for the vSphere hosts were captured by using VMware vCenter Server The figures here show the
CPU memory and network utilization for boot storm login storm and steady state of one of the vSphere
servers hosting the virtual desktops The results shown here are for a test run with 800 no standard user
desktops in the desktop pool
27 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 9 Average CPU performance per core on one vSphere host during login storm and steady state
Figure 10 Disk space usage during login storm and steady state
0
10
20
30
40
50
60
70
80
90
100
1020 1045 1110 1135 1200 1225
Per
cen
t
Time
CPU Performance
0
50
100
150
200
250
300
1020 1040 1100 1120 1140 1200 1220
GB
Time
Memory Performance
Granted Swap used Shared common
28 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 11 Overall network performance during login storm and steady state
Figure 12 Storage adapter performance during login storm and steady state
0
10000
20000
30000
40000
50000
60000
70000
1020 1045 1110 1135 1200 1225
kBp
s
Time
Network Performance
0
05
1
15
2
25
1020 1045 1110 1135 1200 1225
mSe
c
Time
Storage adaptor performance
29 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
The key observations from the statistics were
CPU utilization was less than the 85 percent threshold throughout the test
Active disk space usage was about 80 percent during the boost storm and about 60 percent
during login storm and steady state There was minimal-or no memory ballooning observed
Network utilization was about 45 percent which included all the networks such as iSCSI SAN VDI
LAN Management LAN and vMotion LAN
Average read- and write latencies at the storage adapter level were very close to the observed
latencies in Fluid Cache 2 msec
632 Monitoring user experience Figure 13 here shows the response time as experienced by each user as calculated by Login VSI The graph
clearly shows that the VSImax (Dynamic) value has not been reached and there were non-responsive or
inactive sessions This means that the array is capable of supporting the 1000 desktops and all users have
acceptable response times for applications that the user is has started
Figure 13 Login VSI user experience monitoring for 800 standard user desktops
30 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
633 Standard user test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SANndashbased VDI solution is able to host 800 virtual desktops and support
a standard user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only operations and
less than 2 percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to handle this login storm easily with low latency mdash it delivered the required 6500 IOPS with less
than 2 milliseconds of write latency with a 99 percent write VDI IO workload
64 Login storm and steady state with high IOPS (LoginVSI Medium +
Iometer) As mentioned earlier Iometer was used in desktop VMs alongside the Login VSI Medium workload to
simulate high IOPS type of VDI environment To mimic actual VDI workload profile the following Iometer
profile was used
20 KB block size 80 percent write 75 percent random with 25 msec burst delay
Figure 14 here shows the various IO characteristics during the login storm and steady state of these tests
Figure 14 IOPS and Cache Hit for the high IOPS test
On the Fluid Cache layer the maximum IOPS reached was approximately 72000 (or 90 IOPSVM) with
cache write-hit 100 percent and read-hit around 95 percent As shown in the Figure 15 the throughput
peaked at greater than 900 MBps with a peak latency of approximately 75 msec
31 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 15 Throughput and Latency for the high IOPS test
32 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
641 Server host performance Similar to the standard user test statistics for the vSphere hosts were captured by using VMware vCenter
Server during the high IOPS (heavy user) test also There are no significant differences in CPU disk space
and network utilization between standard users and heavy users The storage adapter latency is also
showing similar on hosts and observed on Fluid Cache
642 User experience monitoring Figure 16 here shows the response time as experienced by each user as calculated by Login VSI for the
heavy user test The graph shows that the VSImax (Dynamic) value was 796 indicating that the solution is
capable of supporting the 800 user high IOPS desktops with 90 IOPSVM
Figure 16 Login VSI user experience monitoring for 800 user high IOPS desktops
33 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
643 High IOPS (heavy user) test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SAN based VDI solution is able to host 800 virtual desktops and support a
high user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only and less than 2
percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to easily handle this login storm with low latency Subsequently it was able to handle 72000 IOPS
at high IOPS steady state with 90 IOPSVM with a maximum of 75 msec latency
34 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
7 Best practices This section provides the best practices derived from the testing and analysis in Section 6
71 Virtual Desktop Infrastructure This section provides best practices for the implementation of VDI using Dell Fluid Cache for SAN
711 Implement roaming profiles and folder redirection Dell recommends that all users in the VDI environment be configured with roaming profiles and folder
redirection This preserves user profiles and user data across boots while using non-persistent virtual
desktops
Also Dell recommends to use a high performance file service to provide the profile and folder redirection
A separate array may be used to host these volumes for best performance
712 Boot and login storm considerations Section 62 demonstrated the Fluid Cache for SAN performance under boot storm To avoid any potential
IO bursts because of boot storm and degraded user experience and performances Dell recommends that
all or portion of desktops be prebooted Connection brokers such as VMware Horizon View provide the
functionality to configure number of standby desktops
713 Windows 7 master image for desktop VMs Dell recommends that the operating system be customized in order to provide the best performance in a
VDI environment This includes disabling some services which may not be required This can improve
performance for the end user VMware has a specific set of recommendations and settings for Windows 7
and Windows 8 that allow for faster logins quicker screen refreshes and generally better performance
The VMware recommendations for Windows 7 and Windows 8 image optimization can be found here
httpwwwvmwarecomresourcestechresources10157
714 VDI Management infrastructure recommendations Dell recommends to have redundancy and load balancing for all VDI management services in the case of
VMware Horizon View solution as tested here the vSphere Server VMware Horizon View Servers and SQL
Servers Ideally these should be running on clustered hosts with VMware vSphere DRS (distributed
resource scheduler) and HA (high availability) enabled
72 Server host The vSphere servers hosting the infrastructure service providers and the virtual desktops are
recommended to be configured as follows
35 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Follow VMware and Dell best practices for installing and configuring vSphere
Separate virtual switches to segregate iSCSI SAN traffic VDI traffic vMotion traffic and Management
network traffic
Each network path must be assigned to a minimum of two physical NICs for high availability
VMware Knowledge Base article about best practices for installing vSphere 55
httpkbvmwarecomkb2052329
73 Network layer Dell recommends that at least two physical NICs on each vSphere server be dedicated to the VDI network
Use VLANs to segregate different types of network traffic on the same physical network In this case Dell
recommends to separate the infrastructure vMotion and VDI LAN traffic in to separate VLANs
Do not use VLANs to segregate iSCSI SAN and Fluide Cache traffic It is required that SAN and Cache traffic
be on separate dedicated physical network to provide the best performance
Virtual switches in vSphere have a default limit of 120 ports If the number of virtual desktops on each host
exceeds the available ports vSwitch properties should be changed to support the required number of
virtual desktops This change requires a restart of the host vSphere server
On iSCSI SAN switches Spanning tree must be disabled on switch ports connected to end devices for
server and storage ports The PortFast setting must be enabled in the switch configuration for these ports
Jumbo frames and Flow control (if the NICs support it) should be enabled for all components of the iSCSI
network
More information about configuring Dell Networking switches for use with Dell Storage iSCSI SANs is
available here
httpencommunitydellcomtechcenterstoragewwiki4250switch-configuration-guides-by-sisaspx
74 Storage The Dell SC storage arrays combined with Fluid Cache is an excellent platform for providing cost-effective
performance in VDI environments
Fluid Cache for SAN extends the power of Compellent intelligent data placement from the SAN to the
server By providing a single infrastructure for data at both high- and low ends of the performance
spectrum Fluid Cache for SAN with Storage Center 65 array software eliminates the tradeoffs between
server performance and full-featured SAN benefits such as reliability manageability and data protection
Dell recommends to have separate volumes for base image and virtual desktops This enables better
manageability of the volumes easier performance monitoring and allows easy future growth
Dell recommends to use a separate high performance file service to provide file shares for roaming
profiles and user shares
36 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
8 Conclusion The technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed by using a Horizon View VDI platform leveraging Dell Fluid Cache for SAN The storage IO
characteristics under various VDI workload scenarios (boot storm login storm and steady state) along
with performance characteristics throughout the VDI stack (for example vSphere server performance and
user experience) demonstrate the optimal configuration of the infrastructure used for this VDI
deployment For more information about Fluid Cache contact your Dell account manager
37 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
A Horizon view solution configuration
Table 7 Hardware components
Hardware components Description
Virtual Desktops 4 timesDell PowerEdge R720 Servers (Fluid Cache Providers)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
2times350 GB Dell Express Flash PCIe SSDs
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
4 x Dell PowerEdge R720 Servers (Fluid Cache Clients)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55 U2 on all R720 servers Windows 7 (64 Bit) VMs
Infrastructure Servers 2 x Dell PowerEdge R720 servers
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
96 GB RAM
2times300 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55U2 on all R720 servers VMs are loaded with Microsoft Windows 2008 R2
Active Directory
VMware Horizon View 60 Server 1
VMware Horizon View 60 Server 2
VMware vCenter Server 55 update 2
VMware Horizon View Composer
SQL Server
File Server
Login VSI Launchers 8 x Dell PowerEdge M610 servers
2timesIntelreg Xeonreg E-5503 200 GHz Processors
16 GB RAM
4times146 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57711 10GbE NIC
ESXi 51 installed on all R810 servers VMs are loaded with Microsoft Windows 7 64bit Each VM supports up to 30 Login VSI launcher sessions
38 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Network Management VDI LAN
1timesDell Force10 S55 1Gb Ethernet Switch
iSCSI SAN
1timesDell Force10 S4810 10Gb Ethernet Switch
Cache network
1timesDell Force10 S4810 10Gb Ethernet Switch
One Force10 S4810 switch might suffice for all the cache iSCSI SAN VDI LAN and management traffic
Storage 2timesDell Compellent SC8000 controllers 4times6Gb SAS 4-port PCI-E Full-height cards for back-end connectivity 2times10Gb iSCSI 2 port PCI-E Low-profile IO cards for front end connectivity 1timesDell Compellent SC200 disk enclosures 12times4TB NL-SAS 6Gb 72K 35rdquo drives
User Data Infrastructure VMs Virtual Desktops
Performance Monitoring
Dell Compellent Enterprise Manager Dell Fluid Cache for SAN performance monitoring tool () vCenter Performance monitoring Liquidware Stratusphere UX
Performance monitoring on Compellent arrays Fluid Cache performance monitoring Performance monitoring and capture at the ESXi host User experience monitoring on the virtual desktop
39 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 8 Software components
Software components Description Version
Dell Fluid Cache for SAN 20
Dell Compellent Storage Center 64
Dell Compellent Enterprise Manager 64
VMware Horizon View Server 60
VMware Horizon View Composer 60
VMware Horizon View Agent 60
VMware Horizon View Client 64-bit 60
VMware ESXi Hypervisor 55 U2
VMware vCenter Server 55 U2
Microsoft SQL Server 2008R2 Enterprise x64 105016001
Client VM OS Microsoft Windows 7 Enterprise x64 SP1
Management VM OS Microsoft Windows Server 2008 Enterprise R2 x64 SP1
Microsoft Office MS office 2010 Standard Service Pack 1
Login VSI Version 40
Iometer 20060727
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
4 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
6 Test results and analysis 22
61 Test scenarios 22
62 Boot storm IO 23
63 Login storm and steady state for standard users (LoginVSI Medium) 24
631 Server host performance 26
632 Monitoring user experience 29
633 Standard user test results summary 30
64 Login storm and steady state for heavy users (LoginVSI Medium + Iometer) 30
641 Server host performance 32
642 User experience monitoring 32
643 Heavy user test results summary 33
7 Best practices 34
71 Virtual Desktop Infrastructure 34
711 Implement roaming profiles and folder redirection 34
712 Boot and login storm considerations 34
713 Windows 7 master image for desktop VMs 34
714 VDI Management infrastructure recommendations 34
72 Server host 34
73 Network layer 35
74 Storage 35
8 Conclusion 36
A Horizon view solution configuration 37
B vSphere host network configuration 40
B1 vSwitch ndash Management traffic 40
B2 vSwitch - iSCSI 40
B3 vSwitch ndash Fluid Cache network 41
B4 vSwitch3 41
Additional resources 42
Acknowledgements 43
Feedback 43
5 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Executive summary
A Virtual Desktop Infrastructure (VDI) deployment can place high storage capacity and performance
demands on the storage platform For example consolidating large amounts of inexpensive stand-alone
desktop storage in to a centralized infrastructure can create tremendous storage capacity demands on
centrally managed shared storage used in VDI deployments Performance demands are determined by
the number of IO operations per second (IOPS) generated by basic desktop client operations such as
system boot logon and logoff and by desktop usage operations from different users Storm events such
as simultaneous booting of many desktops morning logons and afternoon logoffs by many users at
approximately the same time and virus scan can cause IO requirement variances that place high
performance demands on the storage infrastructure
Current VDI solutions in the market can cost-effectively manage desktop virtualization use cases where
performance demands are not really demanding For example a task worker environment in a call center
can generate 5ndash10 IOPSVM or a knowledge worker environment in an office can generate 15ndash25
IOPSVM Typically hybrid arrays or all-flash arrays are deployed to accommodate performance needs in
these VDI environments
The next frontier for VDI to conquer is the high IOPS use cases such as a software developer organization
or an engineering CADCAM team In these use cases not only the capacity demands are large
(repositories for code or design in development) but also performance demands are extremely high
(often 50ndash80 IOPSVM)
Dell Fluid Cache for SAN mdashan innovative server-side readwrite caching solution for workload
acceleration can provide an innovative cost-effective solution for high IOPS type VDI environments
Even though these VDI environments need a lot of storage capacity the working set is typically relatively
small However this working set is very IO intensivemdashmore read operations (write operations) during
boot storms and more write-operations during steady state Fluid Cache software can provide extremely
high IOPS with minimal latency for these working set VDI data leveraging PCIe SSDs as readwrite cache
pool in the computational tier while a Dell Compellent SAN storage array can provide the performance
and large capacity needed for the shared storage This combination fits perfectly for high IOPS VDI
environment
This technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed in a VMware Horizon View VDI infrastructure leveraging Fluid Cache and Compellent storage
array The test infrastructure also included Dell Networking switches and Dell PowerEdge servers running
VMware vSphere 55 as the hypervisor In the test environment the solution infrastructure successfully
hosted 800 desktops with satisfactory performance results across all layers of the stack including the
user layer hypervisor layer and storage layer while delivering approximately 90 IOPSVM as a sustained
steady state load Fluid Cache performance ensured excellent end-user desktop application response
times as determined by the user-level experience monitoring software LoginVSIrsquos VSIMax Details are
provided for the storage IO characteristics about various VDI workload scenarios such as boot and login
storms along with performance characteristics throughout the VDI stack
6 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
1 Introduction Desktop virtualization platforms such as VMware Horizon View 60 (Horizon View) can provide
organizations with significant cost savings streamlined implementation and ease of desktop
management In order to achieve these VDI benefits and to ensure optimal user experience the end-to-
end infrastructure design and sizing considerations need to be addressed carefully While VDI workloads
for task and knowledge workers are correctly understood by using many cost-effective solutions that are
available the high IOPS 800-user VDI use cases are addressed less often because current solutions
typically do not meet the stringent performance- and capacity requirements of these use cases in an
economically sensible manner
The goal of this technical white paper is to present the results of a series of storage IO performance tests
and provide the optimal end-to-end infrastructure design for high IOPS 800-user type VDI environments
leveraging Dell Fluid Cache for SAN Dell Compellent SAN storage arrays Dell PowerEdge servers and Dell
Networking switches
11 Objectives The primary objectives of the tests conducted for this technical white paper are
Develop an optimal end-to-end infrastructure design for a Horizon View and vSphere-based
heavy user type VDI solution deployed by using the Fluid Cache Compellent storage PowerEdge
servers and Dell Networking switches
Determine the performance at every layer of the VDI solution stack under high IOPS workload For
example desktops generating 80ndash90 IOPSVM at steady state
Determine the performance impact of peak IO activity such as boot and login storms
The test infrastructure used for the tests included
VMware Horizon View 60
VMware vSphere 55 hypervisor
Dell PowerEdge R720 servers with Dell Express PCIe SSDs
Dell Networking S4810 switches
Dell Compellent SC8000 storage array
111 Audience This technical white paper is intended for solution architects storage network engineers system
administrators and IT managers who need to understand about designing properly sizing and deploying
Horizon View-based VDI solutions by using Dell infra design properly sizing and deploying Horizon View-
based VDI solutions by using Dell infrastructure It is expected that the reader has a working knowledge of
the Horizon View architecture vSphere system administration iSCSI SAN network design and Dell
Compellent SAN operation
7 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
2 Dell Fluid Cache for SAN and VDI Dell Fluid Cache for SAN utilizes direct-attached Dell PowerEdge Express Flash NVMe PCIe SSDs and
remote direct memory access (RDMA) networking capabilities to create a clustered caching pool for
improved storage workload performance Applications write directly to the cache pool the
acknowledgement is sent back to the application and in the background the IO is flushed to the external
storage array Data is copied in to the cache pool when it is accessed (read) by application and is available
from the cache pool for reread operations Also data that is written into the cache pool by the application
is then available for reread operations from the application A high-speed link to other cache nodes in the
Fluid Cache for SAN pool allows the data to remain highly available by replicating blocks of data even if a
single node in cache pool stops working Fluid Cache for SAN provides a single management interface and
provides other capabilities such as cache-aware snapshots and replication and compression
Figure 1 shows an example environment highlighting how Fluid Cache for SAN communicates between
server and storage Three nodes are required to run Dell Fluid Cache for SAN software Two of these three
nodes are required to have a minimum of one Dell PowerEdge Express Flash NVMe PCIe SSD each and
the network for private cache network is based on the low-latency RDMA protocol The RDMA network
handles the cache pool communication between the nodes Creation and management of the Fluid
Cache cluster are accomplished by using the Dell Compellent Enterprise Manager software through
automatic cache server discovery
Figure 1 Dell Fluid Cache for SAN communication
8 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Fluid Cache for SAN is an ideal solution for high IOPS type VDI environment with highly write-intensive
workloads because it provides extremely fast and low-latency server-side write back caching Because
writes are mirrored across high-speed network and later destaged to the SAN with significant write
coalescing this solution can sustain significantly higher IOPSVM than an external hybrid or all-flash array
ndashbased solution could
9 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
3 Solution architecture The overall architecture of the VDI solution for the high IOPS environment is shown in the figure here
Figure 2 VDI solution architecture
31 Software Horizon view Horizon View is a VDI solution that includes a complete suite of tools for delivering desktops as a secure
and managed service from a centralized infrastructure A Horizon View infrastructure consists of many
different software network and hardware layer components This section presents an overview of the key
Horizon View components and technologies that are critical for successful design and deployment of the
VDI environment
10 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
311 Horizon view components A functional list of Horizon View components used in this solution is given in the table here
Table 1 Horizon View components
Component Description
Client Devices Personal computing devices used by end users to run the Horizon View Client These can include special end-point devices such as Dell Wyse end points mobile phones and PCs
Horizon View Connection Server
A software service that acts as a broker for client connections by authenticating and then directing the incoming user requests to the appropriate virtual desktop physical desktop or terminal server
Horizon View Client Software that is used to access the Horizon View desktops
Horizon View Agent A service that runs on all systems used as sources for Horizon View desktops and facilitates network communication between the Horizon View clients and the Horizon View server
Horizon View Administrator
A web-based administration platform for the Horizon View infrastructure components
vCenterreg Server Central administration platform for configuring provisioning and managing VMware virtualized data centers
Horizon View Composer
A service running with Horizon View servers used to create pools of virtual desktops from a shared-base image to reduce storage capacity requirements
312 Virtual desktops Virtual desktops can be classified in to two major categories persistent and non-persistent
Persistent desktop environment All configuration and personalization on the assigned desktop is kept for
the user-between sessions When using persistent desktops an administrator usually has to provision
additional storage along with other administrative requirements such as patching and upgrading of
individual desktops
Non-persistent desktop environment Users are dynamically assigned virtual desktop VMs from a pool of
resources during login This type of virtual desktop does not retain any information between sessions At
logoff all changes are simply discarded and the virtual desktop is returned to the original state Patching
and upgrading non-persistent desktops requires only making the change to the base image and refreshing
or recomposing the virtual desktop pool Thus these desktops are much easier to manage but lack the
potential for persistent user customization
11 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
313 Horizon view desktop pools A desktop pool is a term VMware uses to describe a collection of desktops that are managed as a single
entity by the Horizon View Administrator interface Horizon View desktop pools allow administrators to
group users depending on the type of service the user requires There are two types of pools ndash Automated
and Manual
In Horizon View an Automated Pool is a collection of VMs cloned from a base template while a Manual
pool is created by the Horizon View Manager from existing desktop sources physical or virtual For each
desktop in the Manual pool the administrator selects a desktop source to deliver Horizon View access to
the clients
VMware View Personas profile management features can be used to achieve persistent desktop-like
behavior on non-persistent desktops By using these features an administrator can design a user account
where the configuration settings are written to a remote profile that is stored separately from the virtual
desktop image files This reduces the need for additional management on individual virtual desktops while
still providing a customized user experience
314 Using linked clones Significant storage space savings and increased efficiencies in desktop VM provisioning and administration
are possible when using VMware-linked clones A linked clone is a duplicate VM that shares the same base
image with the original VM but has separate differential data disks to track the differences from the
original one Each linked clone functions as an independent desktop VM with its own unique identity
Because linked clones share the same base image they consume significantly less storage disk space than
a set of completely independent VM images Temporary system data and other data unique to each linked
clone desktop VM are written to separate differential data storage and these temporary changes are
discarded during restart andor user logoff Persistent data such as user profiles applications and user
data can be optionally redirected to a CIFS share With this model software maintenance updates
antivirus remediation and patches need to be applied only on the base image These base image changes
automatically take effect on all linked clones without affecting any user settings and data
To configure linked clones the administrator creates a snapshot of a parent VM image with the required
OS settings and software installed Horizon View Composer first creates a full replica (clone) of the parent
VM and then uses this replica to create linked clones The replica can be placed on the same data store as
the linked clones or on a separate data store
More information about configuring linked clones can be found in the ldquoCreating Desktop Poolsrdquo section of
the VMware Horizon View Online Library here
315 Hypervisor platform VMware vSphere 55 VMware vSphere 55 is the enterprise virtualization platform used for building VDI and cloud
infrastructures VMware vSphere 55 includes three major layers virtualization management and interface
The virtualization layer includes infrastructure and application services The management layer is central
12 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
for configuring provisioning and managing virtualized environments The interface layer includes the
vSphere client and the vSphere web client
Throughout the solution all VMware and Microsoft best practices and prerequisites for core services were
used (NTP DNS Active Directory and others)
32 Hardware Dell infrastructure Figure 3 shows the design of the infrastructure for the Horizon Viewndashbased high IOPS type VDI
deployment that leverages Fluid Cache
An eight-node vSphere server cluster is used to host the virtual desktops Each of these server nodes has a
direct-attached PCIe SSD that is added to the Fluid Cache pool thus making each server a Fluid Cache
Provider (a server contributing to the Fluid Cache capacity) The eight PCIe SSDs were distributed among
all the servers to better balance the load on the Fluid Cache server Fluid Cache server1 These servers
were connected by using a private caching network to provide the Fluid Cache functionality Also the
servers were connected through a separate managementVDI client network and a 10 GB Ethernet iSCSI
SAN network
Another two-node vSphere server cluster is used to host the VDI infrastructure VMs such as vCenter
server View Connection server View Composer server SQL Server and Active Directory etc These
infrastructure servers were connected to the management network and the iSCSI SAN network
The Compellent storage array for the solution has two controllers and a mix of Write Intensive (WI) SSDs
15K SAS HDDs and 72K NL-SAS HDDs to provide the optimal performance and capacity needed for the
solution
Two switches are stacked together for different networks to provide redundancy in the networking layer
Ideally 40 GB Ethernet switches are recommended for the cache network While 1 GB Ethernet switches
can be used for management network it is better to use 10 GB Ethernet switches combining management
and VDI client networks The same 10 GB Ethernet switches can be used for iSCSI SAN also (with different
network traffic segmented by VLANs) provided they have adequate bandwidth needed for the specific VDI
deployment
Information about how this reference architecture was developed ensuring the optimal utilization across
the servers switches and storage arrays is discussed later in the following sections of this technical white
paper
1 Fluid Cache does not require all servers to be a Fluid Cache Provider For example in this case four
servers could have two PCIe SSDs each This configuration with four Fluid Cache Provider and four Fluid Cache Client would have had same capacity for Fluid Cache pool and all eight servers could have taken advantage of Fluid Cache However the chosen configuration for the technical white paper provides better performance the because VDI application caching load is unforming distributed among all the available servers
13 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 3 Infrastructure Set-up for VDI Solution
1 Enterprise Manager Console 2 Management and VDI Client Network 3 vSphere Servers hosting virtual desktops 4 Cache network switches (2)
5 SAN switch 6 Storage Center controllers (2) 7 Storage Center expansion enclosures (2) 8 Server hosting VDI infrastructure VMs
(Server 1) (Server 2)
14 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
4 Solution configuration This section provides information about the solution configuration and test setup for hosting Horizon View
virtual desktops including infrastructure components networking and storage subsystems
41 Host design considerations The entire VDI solution was installed in two vSphere server clusters The clusters included
Figure 4 vSphere server clusters
Infrastructure Cluster Two Dell PowerEdge R720 servers hosting VMs for Active Directory
services VMware vCenter 55 server Horizon View Connection server (primary and secondary)
View Composer server Microsoft Windows Server 2012 R2 based file server and SQL Server 2012
R2
View Client Cluster Eight Dell PowerEdge R720 servers hosting the virtual desktops Each server
had
o 2times10 core Intel Xeon CPU E5-2690v2 300GHz
o 256 GB RAM
o 1times350 GB Dell Express Flash PCIe SSD
o 1timesMellanox Connect ndash X3 card
o 1timesDual-port Broadcom NetXtreme II BCM57810 10 Gigabit NIC
o 1timesQuad-port Broadcom NetXtreme BCM5720 Gigabit NIC
Along with the other servers the above servers 40 LoginVSI launcher VMs were used to generate VDI
workload They can be hosted by two PowerEdge R720 servers or equivalent for VDI load generation
purposes
15 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
42 Network design considerations Figure 5 here shows the network layout of one of the eight PowerEdge R720 servers with vSphere 55
installed
Figure 5 vSphere host network configuration
Three network switches are used in the Fluid Cache for VDI implementation One Force10 S55 1 GB switch
for all management traffic and VDI traffic The management traffic includes hosts and vSphere
management Compellent storage management and so on The networks are segregated by using VLANs
to separate different types of traffic
One Dell Force10 S4810 10 GB switch is used for Fluid Cache cache network which supports all the traffic
between cache layer on eight VDI VM hosts Another Force10 S4810 10 GB switch is used for iSCSI
network between infrastructure hosts VDI VM hosts and Compellent SC8000
Appendix B has extended information on the vSwitch configuration for each vSphere host
16 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
43 Dell Compellent SC8000 storage array configurations The storage used to host the virtual desktops was a Dell Compellent SC8000 array running Storage Center
Operating System (SCOS) 65 All two front-end ports were 10 GB iSCSI and all two back-end ports were
six GB serial-attached SCSI (SAS) The array used two external enclosures with Write Intensive (WI) SSDs
comprising Tier 1 and 15K SAS HDDs comprising Tier 2 for performance Also 72 NL-SAS drives were
used in Tier 3 to provide capacity for user data Table 2 summarizes the storage hardware configuration
Table 2 Storage hardware components
Storage role Type Qty Description
Controllers SC8000 2 System Center Operating System (SCOS) 65
Enclosures External 2 24 bay ndash 25rdquo disk drive enclosure
Ports Ethernet ndash 10 Gbps 2 Front end host connectivity
SAS - 6 Gbps 4 Back end drive connectivity
Drives 400 GB WI SSD 12 11 active with 1 hot spare
300 GB 15K SAS HDD
21 20 active with 1 hot spare
4 TB 72K NL-SAS HDD
12 11 active with 1 hot spare
The volumes created to host the virtual desktops took advantage of the Compellent Dynamic Capacity
technology for efficient capacity allocation Table 3 lists the volume layout used for the infrastructure
functions including user data
Table 3 Volume layout for hosting infrastructure components and user data
Volume name Size Purpose
Infrastructure 500 GB Storage for Active Directory SQL Server vCenter Server View Connection Server View Composer and File Server
UserSpace 2 TB Storage for User profiles and folder redirection space (Average 25 GB per user)
Along with the infrastructure volumes the storage array also provided shared storage for hosting the
virtual desktops The volume layout used for configuring the base image (View Composer Replica) and VDI
volumes on the array is shown in Table 4
17 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 4 Dell Storage PS4210XS layout for volumes hosting virtual desktops
Volume name Size Purpose
View-Replicas1 and 2 100 GB each Storage for base image for VDI deployment
VDI-Images1 through 8 500 GB each Storage for VDI VMs in VDI Cluster Each volume hosted 100 desktops
44 vSphere host network configuration VMware vSphere 55 hypervisor was installed on all servers The network configuration on each of those
hosts is described here Each vSphere host was configured with five virtual switches vSwitch0 vSwitch1
vSwitch2 vSwitch3 and vSwitch4 to separate different types of traffic on the system
Table 5 vSwitch configuration in vSphere hosts
vSwitch Description
vSwitch0 Management Network
vSwitch1 and vSwitch2 iSCSI SAN
vSwitch3 Fluid Cache VLAN
vSwitch4 VDI LAN
For additional information about individual vSwitch configuration refer to Appendix B in the Dell technical
white paper
45 Horizon view configuration Horizon View 60 was installed by using the documentation provided by VMware
Horizon View 601 installation documentation
httpswwwvmwarecomsupportpubsview_pubshtml
Table 6 Specific configuration used in the tests
Purpose Count Type Memory CPU
Horizon View Connection Servers
2 VM 16 GB 8nos
View Composer Server 1 VM 8 GB 8nos
18 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
46 Windows 7 VM configuration Following the guidelines from VMware and Login VSI the Windows 7 base image was generated based on
a generic base VM with the following properties
VMware Virtual Hardware version 8
Two virtual CPU
3 GB RAM with 15GB reserved
25 GB virtual hard drive
One virtual NIC connected to the VDI network
Windows 7 64-bit OS
Also the base image was customized by using the VMware Horizon with View Optimization Guide for
Windows 7 and Windows 8 available at this location httpwwwvmwarecomfilespdfVMware-View-
OptimizationGuideWindows7-ENpdf
19 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
5 Horizon view test methodology This section outlines the test objectives along with the test tools and criteria used to determine the
optimal virtual desktop density and best practices for deploying Horizon View on Dell Fluid Cache for SAN
for high IOPS type VDI environment
51 Test objectives As noted in Section 11 the test objectives were
Develop an optimal end-to-end infrastructure design for a Horizon View and vSpherendashbased high
user type of VDI solution deployed by using the Fluid Cache Compellent storage PowerEdge
servers and Dell Networking switches
Determine the performance at every layer of the VDI solution stack under high IOPS workload For
example desktops generating 80ndash90 IOPSVM at steady state
Determine the performance impact of peak IO activity such as boot and login storms
52 Test tools All tests were conducted by using Login VSI 40 as the workload generator and user experience analyzer
tool Login VSI is a benchmarking tool to measure the performance and scalability of centralized desktop
environments such as Server Based Computing (SBC) and VDI
Note More information can be found at the Login VSI website httpwwwloginvsicom
In addition to Login VSI Iometer is used in desktop VMs to simulate high IOPS conditions Iometer is
invoked in desktop VMs by using custom scripting of Login VSI workloads
Note More information can be found at the Iometer project website httpwwwiometerorg
521 Load generation First the ldquoMediumrdquo workload from Login VSI was used to simulate the standard user workload The
characteristics of the Medium workload are
Up to five applications are started simultaneously
Applications include Microsoft Internet Explorer Microsoft Word Microsoft Excel Microsoft
PowerPoint PDF reader 7-Zip compression software Movie player and FreeMind
After a session is started the medium workload repeats approximately after every 48 minutes
During a loop the response time is measured after every 3ndash4 minutes
Idle time is about two minutes in each 48-minute loop
Type rate is approximately 160 milliseconds per character
After the test by using Login VSI Medium was complete tests were rerun with Login VSI Medium and
Iometer in desktop VMs to simulate high IOPS VDI workload While the Login VSI Medium generates 8ndash10
20 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
IOPSVM the latter method was able to generate 80ndash90 IOPSVM For these tests each VM in the Horizon
view pool is created with standard LoginVSI contents and applications Also Iometer is installed on each
VM After the user logs in a customized logon script starts the Iometer with required IO specification (icf
file)
522 Monitoring tools The following monitoring tools were used
Dell Compellent Enterprise Manager for monitoring Fluid Cache and Compellent SC8000 storage
array performance
VMware vCenter statistics for vSphere performance
Login VSI Analyzer for end user performance statistics
Detailed performance metrics were captured from the storage arrays hypervisors virtual desktops and
the load generators during the tests
53 Test criteria The primary focus of the tests is to validate the 800 desktop high IOPS type of VDI architecture with
acceptable user experience by using Fluid Cache for SAN VDI configurations involve many components at
different layers ndash application hypervisor server network and storage As a result multiple metrics need to
be captured at different layers to ensure that the environment is healthy and performing optimally and
appropriately for all users
The specific test criteria are described in the following sections
531 Storage capacity and IO latency The typical industry standard latency limit for storage disk IO is 10 milliseconds Maintaining this limit
ensures good user application response times when there are no other bottlenecks at the infrastructure
layer In addition Dell recommends to maintain a 10 percent spare disk space on the storage array for
optimal performance
532 System utilization at the hypervisor Even though the primary focus of these tests was storage characterization additional metrics at the
hypervisor infrastructure layer were defined to ensure solution consistency These were
CPU utilization on any vSphere server must not exceed 85 percent
Minimal memory ballooning on the VMs
Total network bandwidth utilization must not exceed 90 percent on any one link
TCPIP storage network retransmissions should be less than 05 percent
21 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
533 Virtual desktop user experience Login VSI Analyzer was also used to gather metrics on the user experience at the virtual desktop layer to
ensure that all the desktops had acceptable levels of application performance Login VSI uses the VSImax
parameter to determine the maximum number of sessions that can be obtained from a deployed solution
The calculation methodology used in VSImax is available here
httpwwwloginvsicomdocumentationindexphptitle=Analyzing_Results
534 Test configuration A single virtual desktop pool was configured by using the VMware Horizon View Administrator interface
Each pool was built from a Windows 7 base image The Windows 7 configuration information is available
in Section 46
Desktop pool properties
Automatic Desktop Pool
Users are assigned using Floating assignments
View Storage Accelerator is enabled for all hosts with a refresh period of seven days
800 desktops were deployed across eight hosts (100 desktops a host)
Replica images were stored on a separate volume
22 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
6 Test results and analysis This section presents the results from the different Horizon View VDI characterization tests and the key
findings from each test The testing was focused on the high IOPS workload profile
61 Test scenarios The following tests were conducted to gather results and analysis on the solution stack
1 Boot storm Boot storms represent the worst-case scenario where many virtual desktops are
turned on at the same time and they all contend for the system resources simultaneously This test
was used to evaluate if the storage array hosting the desktops was capable of handling huge
variation in storage IO without causing significant impact on other services
2 Login storm Login storms also represent a high IOPS situation where many users are logging in to
their virtual desktops at the beginning of a workday or a shift In this test all the desktops were
pre-booted and left in an idle state for more than 20 minutes to let their IO settle before running
the Login VSI Medium workload to simulate users logging in to their virtual desktops
3 Steady state workload for standard users with normal IOPS After the login storm for the previous
test was completed the Login VSI Medium workload was allowed to run for at least one hour to
simulate the real-world scenario of users performing their daily tasks The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
4 Steady state workload for users with high IOPS The previous test was repeated with the Login
VSI Medium workload and Iometer scripts in desktop VMs as described in Section 521 to simulate
real-world heavy users performing their daily tasks with high IOPS The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
The following sections provide results from the boot storm login storm and steady state testing for the
Fluid Cache for SAN based VDI solution
23 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
62 Boot storm IO To simulate a boot storm the virtual desktops were reset simultaneously from the VMware vSphere client
Figure 6 shows the IO pattern on the Fluid Cache for the boot storm
Figure 6 SAN HQ data showing boot storm performance with Fluid Cache array
With 800 desktops the boot storm generated about 115000 total IOPS with a majority of them being
write operations All desktops were available for use in less than four minutes
24 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
63 Login storm and steady state for standard users (LoginVSI
Medium) Login VSI was programmed to start 800 virtual desktops over a period of about 60 minutes after pre-
booting the virtual desktops The peak IOPS during the login storm observed by the vSphere servers
hosting the desktops was about 6500 IOPS (8ndash10 IOPS a VM)
In a standard user environment login storms generate significantly more write IOPS than a boot storm or
steady state because of multiple factors such as
User profile activity
Starting operating system services on the desktop
First start of applications
After a virtual desktop has achieved a steady state after user login the Windows 7 OS has cached
applications in memory and does not need to access storage each time the application is started This
leads to lesser IOPS during the steady state Figure 7 here shows the various IO characteristics during the
login storm and steady state of these tests
25 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 7 IOPS and Cache Hit for the standard user test
On the Fluid Cache layer the maximum IOPS reached 6500 with cache-hit reaching 100 percent and
read-hit around 95 percent As shown in the Figure 8 here the throughput peaked at 98 MBps with a low
latency of less than 2 msec
26 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 8 Throughput and Latency for the standard user test
631 Server host performance During the login storm and steady state of the test the vSphere host CPU memory network and storage
performance were measured on all the servers that hosted the virtual desktops The performance of one
such vSphere server is given here The other vSphere servers had similar performance characteristics
Statistics for the vSphere hosts were captured by using VMware vCenter Server The figures here show the
CPU memory and network utilization for boot storm login storm and steady state of one of the vSphere
servers hosting the virtual desktops The results shown here are for a test run with 800 no standard user
desktops in the desktop pool
27 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 9 Average CPU performance per core on one vSphere host during login storm and steady state
Figure 10 Disk space usage during login storm and steady state
0
10
20
30
40
50
60
70
80
90
100
1020 1045 1110 1135 1200 1225
Per
cen
t
Time
CPU Performance
0
50
100
150
200
250
300
1020 1040 1100 1120 1140 1200 1220
GB
Time
Memory Performance
Granted Swap used Shared common
28 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 11 Overall network performance during login storm and steady state
Figure 12 Storage adapter performance during login storm and steady state
0
10000
20000
30000
40000
50000
60000
70000
1020 1045 1110 1135 1200 1225
kBp
s
Time
Network Performance
0
05
1
15
2
25
1020 1045 1110 1135 1200 1225
mSe
c
Time
Storage adaptor performance
29 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
The key observations from the statistics were
CPU utilization was less than the 85 percent threshold throughout the test
Active disk space usage was about 80 percent during the boost storm and about 60 percent
during login storm and steady state There was minimal-or no memory ballooning observed
Network utilization was about 45 percent which included all the networks such as iSCSI SAN VDI
LAN Management LAN and vMotion LAN
Average read- and write latencies at the storage adapter level were very close to the observed
latencies in Fluid Cache 2 msec
632 Monitoring user experience Figure 13 here shows the response time as experienced by each user as calculated by Login VSI The graph
clearly shows that the VSImax (Dynamic) value has not been reached and there were non-responsive or
inactive sessions This means that the array is capable of supporting the 1000 desktops and all users have
acceptable response times for applications that the user is has started
Figure 13 Login VSI user experience monitoring for 800 standard user desktops
30 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
633 Standard user test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SANndashbased VDI solution is able to host 800 virtual desktops and support
a standard user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only operations and
less than 2 percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to handle this login storm easily with low latency mdash it delivered the required 6500 IOPS with less
than 2 milliseconds of write latency with a 99 percent write VDI IO workload
64 Login storm and steady state with high IOPS (LoginVSI Medium +
Iometer) As mentioned earlier Iometer was used in desktop VMs alongside the Login VSI Medium workload to
simulate high IOPS type of VDI environment To mimic actual VDI workload profile the following Iometer
profile was used
20 KB block size 80 percent write 75 percent random with 25 msec burst delay
Figure 14 here shows the various IO characteristics during the login storm and steady state of these tests
Figure 14 IOPS and Cache Hit for the high IOPS test
On the Fluid Cache layer the maximum IOPS reached was approximately 72000 (or 90 IOPSVM) with
cache write-hit 100 percent and read-hit around 95 percent As shown in the Figure 15 the throughput
peaked at greater than 900 MBps with a peak latency of approximately 75 msec
31 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 15 Throughput and Latency for the high IOPS test
32 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
641 Server host performance Similar to the standard user test statistics for the vSphere hosts were captured by using VMware vCenter
Server during the high IOPS (heavy user) test also There are no significant differences in CPU disk space
and network utilization between standard users and heavy users The storage adapter latency is also
showing similar on hosts and observed on Fluid Cache
642 User experience monitoring Figure 16 here shows the response time as experienced by each user as calculated by Login VSI for the
heavy user test The graph shows that the VSImax (Dynamic) value was 796 indicating that the solution is
capable of supporting the 800 user high IOPS desktops with 90 IOPSVM
Figure 16 Login VSI user experience monitoring for 800 user high IOPS desktops
33 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
643 High IOPS (heavy user) test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SAN based VDI solution is able to host 800 virtual desktops and support a
high user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only and less than 2
percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to easily handle this login storm with low latency Subsequently it was able to handle 72000 IOPS
at high IOPS steady state with 90 IOPSVM with a maximum of 75 msec latency
34 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
7 Best practices This section provides the best practices derived from the testing and analysis in Section 6
71 Virtual Desktop Infrastructure This section provides best practices for the implementation of VDI using Dell Fluid Cache for SAN
711 Implement roaming profiles and folder redirection Dell recommends that all users in the VDI environment be configured with roaming profiles and folder
redirection This preserves user profiles and user data across boots while using non-persistent virtual
desktops
Also Dell recommends to use a high performance file service to provide the profile and folder redirection
A separate array may be used to host these volumes for best performance
712 Boot and login storm considerations Section 62 demonstrated the Fluid Cache for SAN performance under boot storm To avoid any potential
IO bursts because of boot storm and degraded user experience and performances Dell recommends that
all or portion of desktops be prebooted Connection brokers such as VMware Horizon View provide the
functionality to configure number of standby desktops
713 Windows 7 master image for desktop VMs Dell recommends that the operating system be customized in order to provide the best performance in a
VDI environment This includes disabling some services which may not be required This can improve
performance for the end user VMware has a specific set of recommendations and settings for Windows 7
and Windows 8 that allow for faster logins quicker screen refreshes and generally better performance
The VMware recommendations for Windows 7 and Windows 8 image optimization can be found here
httpwwwvmwarecomresourcestechresources10157
714 VDI Management infrastructure recommendations Dell recommends to have redundancy and load balancing for all VDI management services in the case of
VMware Horizon View solution as tested here the vSphere Server VMware Horizon View Servers and SQL
Servers Ideally these should be running on clustered hosts with VMware vSphere DRS (distributed
resource scheduler) and HA (high availability) enabled
72 Server host The vSphere servers hosting the infrastructure service providers and the virtual desktops are
recommended to be configured as follows
35 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Follow VMware and Dell best practices for installing and configuring vSphere
Separate virtual switches to segregate iSCSI SAN traffic VDI traffic vMotion traffic and Management
network traffic
Each network path must be assigned to a minimum of two physical NICs for high availability
VMware Knowledge Base article about best practices for installing vSphere 55
httpkbvmwarecomkb2052329
73 Network layer Dell recommends that at least two physical NICs on each vSphere server be dedicated to the VDI network
Use VLANs to segregate different types of network traffic on the same physical network In this case Dell
recommends to separate the infrastructure vMotion and VDI LAN traffic in to separate VLANs
Do not use VLANs to segregate iSCSI SAN and Fluide Cache traffic It is required that SAN and Cache traffic
be on separate dedicated physical network to provide the best performance
Virtual switches in vSphere have a default limit of 120 ports If the number of virtual desktops on each host
exceeds the available ports vSwitch properties should be changed to support the required number of
virtual desktops This change requires a restart of the host vSphere server
On iSCSI SAN switches Spanning tree must be disabled on switch ports connected to end devices for
server and storage ports The PortFast setting must be enabled in the switch configuration for these ports
Jumbo frames and Flow control (if the NICs support it) should be enabled for all components of the iSCSI
network
More information about configuring Dell Networking switches for use with Dell Storage iSCSI SANs is
available here
httpencommunitydellcomtechcenterstoragewwiki4250switch-configuration-guides-by-sisaspx
74 Storage The Dell SC storage arrays combined with Fluid Cache is an excellent platform for providing cost-effective
performance in VDI environments
Fluid Cache for SAN extends the power of Compellent intelligent data placement from the SAN to the
server By providing a single infrastructure for data at both high- and low ends of the performance
spectrum Fluid Cache for SAN with Storage Center 65 array software eliminates the tradeoffs between
server performance and full-featured SAN benefits such as reliability manageability and data protection
Dell recommends to have separate volumes for base image and virtual desktops This enables better
manageability of the volumes easier performance monitoring and allows easy future growth
Dell recommends to use a separate high performance file service to provide file shares for roaming
profiles and user shares
36 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
8 Conclusion The technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed by using a Horizon View VDI platform leveraging Dell Fluid Cache for SAN The storage IO
characteristics under various VDI workload scenarios (boot storm login storm and steady state) along
with performance characteristics throughout the VDI stack (for example vSphere server performance and
user experience) demonstrate the optimal configuration of the infrastructure used for this VDI
deployment For more information about Fluid Cache contact your Dell account manager
37 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
A Horizon view solution configuration
Table 7 Hardware components
Hardware components Description
Virtual Desktops 4 timesDell PowerEdge R720 Servers (Fluid Cache Providers)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
2times350 GB Dell Express Flash PCIe SSDs
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
4 x Dell PowerEdge R720 Servers (Fluid Cache Clients)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55 U2 on all R720 servers Windows 7 (64 Bit) VMs
Infrastructure Servers 2 x Dell PowerEdge R720 servers
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
96 GB RAM
2times300 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55U2 on all R720 servers VMs are loaded with Microsoft Windows 2008 R2
Active Directory
VMware Horizon View 60 Server 1
VMware Horizon View 60 Server 2
VMware vCenter Server 55 update 2
VMware Horizon View Composer
SQL Server
File Server
Login VSI Launchers 8 x Dell PowerEdge M610 servers
2timesIntelreg Xeonreg E-5503 200 GHz Processors
16 GB RAM
4times146 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57711 10GbE NIC
ESXi 51 installed on all R810 servers VMs are loaded with Microsoft Windows 7 64bit Each VM supports up to 30 Login VSI launcher sessions
38 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Network Management VDI LAN
1timesDell Force10 S55 1Gb Ethernet Switch
iSCSI SAN
1timesDell Force10 S4810 10Gb Ethernet Switch
Cache network
1timesDell Force10 S4810 10Gb Ethernet Switch
One Force10 S4810 switch might suffice for all the cache iSCSI SAN VDI LAN and management traffic
Storage 2timesDell Compellent SC8000 controllers 4times6Gb SAS 4-port PCI-E Full-height cards for back-end connectivity 2times10Gb iSCSI 2 port PCI-E Low-profile IO cards for front end connectivity 1timesDell Compellent SC200 disk enclosures 12times4TB NL-SAS 6Gb 72K 35rdquo drives
User Data Infrastructure VMs Virtual Desktops
Performance Monitoring
Dell Compellent Enterprise Manager Dell Fluid Cache for SAN performance monitoring tool () vCenter Performance monitoring Liquidware Stratusphere UX
Performance monitoring on Compellent arrays Fluid Cache performance monitoring Performance monitoring and capture at the ESXi host User experience monitoring on the virtual desktop
39 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 8 Software components
Software components Description Version
Dell Fluid Cache for SAN 20
Dell Compellent Storage Center 64
Dell Compellent Enterprise Manager 64
VMware Horizon View Server 60
VMware Horizon View Composer 60
VMware Horizon View Agent 60
VMware Horizon View Client 64-bit 60
VMware ESXi Hypervisor 55 U2
VMware vCenter Server 55 U2
Microsoft SQL Server 2008R2 Enterprise x64 105016001
Client VM OS Microsoft Windows 7 Enterprise x64 SP1
Management VM OS Microsoft Windows Server 2008 Enterprise R2 x64 SP1
Microsoft Office MS office 2010 Standard Service Pack 1
Login VSI Version 40
Iometer 20060727
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
5 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Executive summary
A Virtual Desktop Infrastructure (VDI) deployment can place high storage capacity and performance
demands on the storage platform For example consolidating large amounts of inexpensive stand-alone
desktop storage in to a centralized infrastructure can create tremendous storage capacity demands on
centrally managed shared storage used in VDI deployments Performance demands are determined by
the number of IO operations per second (IOPS) generated by basic desktop client operations such as
system boot logon and logoff and by desktop usage operations from different users Storm events such
as simultaneous booting of many desktops morning logons and afternoon logoffs by many users at
approximately the same time and virus scan can cause IO requirement variances that place high
performance demands on the storage infrastructure
Current VDI solutions in the market can cost-effectively manage desktop virtualization use cases where
performance demands are not really demanding For example a task worker environment in a call center
can generate 5ndash10 IOPSVM or a knowledge worker environment in an office can generate 15ndash25
IOPSVM Typically hybrid arrays or all-flash arrays are deployed to accommodate performance needs in
these VDI environments
The next frontier for VDI to conquer is the high IOPS use cases such as a software developer organization
or an engineering CADCAM team In these use cases not only the capacity demands are large
(repositories for code or design in development) but also performance demands are extremely high
(often 50ndash80 IOPSVM)
Dell Fluid Cache for SAN mdashan innovative server-side readwrite caching solution for workload
acceleration can provide an innovative cost-effective solution for high IOPS type VDI environments
Even though these VDI environments need a lot of storage capacity the working set is typically relatively
small However this working set is very IO intensivemdashmore read operations (write operations) during
boot storms and more write-operations during steady state Fluid Cache software can provide extremely
high IOPS with minimal latency for these working set VDI data leveraging PCIe SSDs as readwrite cache
pool in the computational tier while a Dell Compellent SAN storage array can provide the performance
and large capacity needed for the shared storage This combination fits perfectly for high IOPS VDI
environment
This technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed in a VMware Horizon View VDI infrastructure leveraging Fluid Cache and Compellent storage
array The test infrastructure also included Dell Networking switches and Dell PowerEdge servers running
VMware vSphere 55 as the hypervisor In the test environment the solution infrastructure successfully
hosted 800 desktops with satisfactory performance results across all layers of the stack including the
user layer hypervisor layer and storage layer while delivering approximately 90 IOPSVM as a sustained
steady state load Fluid Cache performance ensured excellent end-user desktop application response
times as determined by the user-level experience monitoring software LoginVSIrsquos VSIMax Details are
provided for the storage IO characteristics about various VDI workload scenarios such as boot and login
storms along with performance characteristics throughout the VDI stack
6 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
1 Introduction Desktop virtualization platforms such as VMware Horizon View 60 (Horizon View) can provide
organizations with significant cost savings streamlined implementation and ease of desktop
management In order to achieve these VDI benefits and to ensure optimal user experience the end-to-
end infrastructure design and sizing considerations need to be addressed carefully While VDI workloads
for task and knowledge workers are correctly understood by using many cost-effective solutions that are
available the high IOPS 800-user VDI use cases are addressed less often because current solutions
typically do not meet the stringent performance- and capacity requirements of these use cases in an
economically sensible manner
The goal of this technical white paper is to present the results of a series of storage IO performance tests
and provide the optimal end-to-end infrastructure design for high IOPS 800-user type VDI environments
leveraging Dell Fluid Cache for SAN Dell Compellent SAN storage arrays Dell PowerEdge servers and Dell
Networking switches
11 Objectives The primary objectives of the tests conducted for this technical white paper are
Develop an optimal end-to-end infrastructure design for a Horizon View and vSphere-based
heavy user type VDI solution deployed by using the Fluid Cache Compellent storage PowerEdge
servers and Dell Networking switches
Determine the performance at every layer of the VDI solution stack under high IOPS workload For
example desktops generating 80ndash90 IOPSVM at steady state
Determine the performance impact of peak IO activity such as boot and login storms
The test infrastructure used for the tests included
VMware Horizon View 60
VMware vSphere 55 hypervisor
Dell PowerEdge R720 servers with Dell Express PCIe SSDs
Dell Networking S4810 switches
Dell Compellent SC8000 storage array
111 Audience This technical white paper is intended for solution architects storage network engineers system
administrators and IT managers who need to understand about designing properly sizing and deploying
Horizon View-based VDI solutions by using Dell infra design properly sizing and deploying Horizon View-
based VDI solutions by using Dell infrastructure It is expected that the reader has a working knowledge of
the Horizon View architecture vSphere system administration iSCSI SAN network design and Dell
Compellent SAN operation
7 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
2 Dell Fluid Cache for SAN and VDI Dell Fluid Cache for SAN utilizes direct-attached Dell PowerEdge Express Flash NVMe PCIe SSDs and
remote direct memory access (RDMA) networking capabilities to create a clustered caching pool for
improved storage workload performance Applications write directly to the cache pool the
acknowledgement is sent back to the application and in the background the IO is flushed to the external
storage array Data is copied in to the cache pool when it is accessed (read) by application and is available
from the cache pool for reread operations Also data that is written into the cache pool by the application
is then available for reread operations from the application A high-speed link to other cache nodes in the
Fluid Cache for SAN pool allows the data to remain highly available by replicating blocks of data even if a
single node in cache pool stops working Fluid Cache for SAN provides a single management interface and
provides other capabilities such as cache-aware snapshots and replication and compression
Figure 1 shows an example environment highlighting how Fluid Cache for SAN communicates between
server and storage Three nodes are required to run Dell Fluid Cache for SAN software Two of these three
nodes are required to have a minimum of one Dell PowerEdge Express Flash NVMe PCIe SSD each and
the network for private cache network is based on the low-latency RDMA protocol The RDMA network
handles the cache pool communication between the nodes Creation and management of the Fluid
Cache cluster are accomplished by using the Dell Compellent Enterprise Manager software through
automatic cache server discovery
Figure 1 Dell Fluid Cache for SAN communication
8 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Fluid Cache for SAN is an ideal solution for high IOPS type VDI environment with highly write-intensive
workloads because it provides extremely fast and low-latency server-side write back caching Because
writes are mirrored across high-speed network and later destaged to the SAN with significant write
coalescing this solution can sustain significantly higher IOPSVM than an external hybrid or all-flash array
ndashbased solution could
9 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
3 Solution architecture The overall architecture of the VDI solution for the high IOPS environment is shown in the figure here
Figure 2 VDI solution architecture
31 Software Horizon view Horizon View is a VDI solution that includes a complete suite of tools for delivering desktops as a secure
and managed service from a centralized infrastructure A Horizon View infrastructure consists of many
different software network and hardware layer components This section presents an overview of the key
Horizon View components and technologies that are critical for successful design and deployment of the
VDI environment
10 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
311 Horizon view components A functional list of Horizon View components used in this solution is given in the table here
Table 1 Horizon View components
Component Description
Client Devices Personal computing devices used by end users to run the Horizon View Client These can include special end-point devices such as Dell Wyse end points mobile phones and PCs
Horizon View Connection Server
A software service that acts as a broker for client connections by authenticating and then directing the incoming user requests to the appropriate virtual desktop physical desktop or terminal server
Horizon View Client Software that is used to access the Horizon View desktops
Horizon View Agent A service that runs on all systems used as sources for Horizon View desktops and facilitates network communication between the Horizon View clients and the Horizon View server
Horizon View Administrator
A web-based administration platform for the Horizon View infrastructure components
vCenterreg Server Central administration platform for configuring provisioning and managing VMware virtualized data centers
Horizon View Composer
A service running with Horizon View servers used to create pools of virtual desktops from a shared-base image to reduce storage capacity requirements
312 Virtual desktops Virtual desktops can be classified in to two major categories persistent and non-persistent
Persistent desktop environment All configuration and personalization on the assigned desktop is kept for
the user-between sessions When using persistent desktops an administrator usually has to provision
additional storage along with other administrative requirements such as patching and upgrading of
individual desktops
Non-persistent desktop environment Users are dynamically assigned virtual desktop VMs from a pool of
resources during login This type of virtual desktop does not retain any information between sessions At
logoff all changes are simply discarded and the virtual desktop is returned to the original state Patching
and upgrading non-persistent desktops requires only making the change to the base image and refreshing
or recomposing the virtual desktop pool Thus these desktops are much easier to manage but lack the
potential for persistent user customization
11 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
313 Horizon view desktop pools A desktop pool is a term VMware uses to describe a collection of desktops that are managed as a single
entity by the Horizon View Administrator interface Horizon View desktop pools allow administrators to
group users depending on the type of service the user requires There are two types of pools ndash Automated
and Manual
In Horizon View an Automated Pool is a collection of VMs cloned from a base template while a Manual
pool is created by the Horizon View Manager from existing desktop sources physical or virtual For each
desktop in the Manual pool the administrator selects a desktop source to deliver Horizon View access to
the clients
VMware View Personas profile management features can be used to achieve persistent desktop-like
behavior on non-persistent desktops By using these features an administrator can design a user account
where the configuration settings are written to a remote profile that is stored separately from the virtual
desktop image files This reduces the need for additional management on individual virtual desktops while
still providing a customized user experience
314 Using linked clones Significant storage space savings and increased efficiencies in desktop VM provisioning and administration
are possible when using VMware-linked clones A linked clone is a duplicate VM that shares the same base
image with the original VM but has separate differential data disks to track the differences from the
original one Each linked clone functions as an independent desktop VM with its own unique identity
Because linked clones share the same base image they consume significantly less storage disk space than
a set of completely independent VM images Temporary system data and other data unique to each linked
clone desktop VM are written to separate differential data storage and these temporary changes are
discarded during restart andor user logoff Persistent data such as user profiles applications and user
data can be optionally redirected to a CIFS share With this model software maintenance updates
antivirus remediation and patches need to be applied only on the base image These base image changes
automatically take effect on all linked clones without affecting any user settings and data
To configure linked clones the administrator creates a snapshot of a parent VM image with the required
OS settings and software installed Horizon View Composer first creates a full replica (clone) of the parent
VM and then uses this replica to create linked clones The replica can be placed on the same data store as
the linked clones or on a separate data store
More information about configuring linked clones can be found in the ldquoCreating Desktop Poolsrdquo section of
the VMware Horizon View Online Library here
315 Hypervisor platform VMware vSphere 55 VMware vSphere 55 is the enterprise virtualization platform used for building VDI and cloud
infrastructures VMware vSphere 55 includes three major layers virtualization management and interface
The virtualization layer includes infrastructure and application services The management layer is central
12 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
for configuring provisioning and managing virtualized environments The interface layer includes the
vSphere client and the vSphere web client
Throughout the solution all VMware and Microsoft best practices and prerequisites for core services were
used (NTP DNS Active Directory and others)
32 Hardware Dell infrastructure Figure 3 shows the design of the infrastructure for the Horizon Viewndashbased high IOPS type VDI
deployment that leverages Fluid Cache
An eight-node vSphere server cluster is used to host the virtual desktops Each of these server nodes has a
direct-attached PCIe SSD that is added to the Fluid Cache pool thus making each server a Fluid Cache
Provider (a server contributing to the Fluid Cache capacity) The eight PCIe SSDs were distributed among
all the servers to better balance the load on the Fluid Cache server Fluid Cache server1 These servers
were connected by using a private caching network to provide the Fluid Cache functionality Also the
servers were connected through a separate managementVDI client network and a 10 GB Ethernet iSCSI
SAN network
Another two-node vSphere server cluster is used to host the VDI infrastructure VMs such as vCenter
server View Connection server View Composer server SQL Server and Active Directory etc These
infrastructure servers were connected to the management network and the iSCSI SAN network
The Compellent storage array for the solution has two controllers and a mix of Write Intensive (WI) SSDs
15K SAS HDDs and 72K NL-SAS HDDs to provide the optimal performance and capacity needed for the
solution
Two switches are stacked together for different networks to provide redundancy in the networking layer
Ideally 40 GB Ethernet switches are recommended for the cache network While 1 GB Ethernet switches
can be used for management network it is better to use 10 GB Ethernet switches combining management
and VDI client networks The same 10 GB Ethernet switches can be used for iSCSI SAN also (with different
network traffic segmented by VLANs) provided they have adequate bandwidth needed for the specific VDI
deployment
Information about how this reference architecture was developed ensuring the optimal utilization across
the servers switches and storage arrays is discussed later in the following sections of this technical white
paper
1 Fluid Cache does not require all servers to be a Fluid Cache Provider For example in this case four
servers could have two PCIe SSDs each This configuration with four Fluid Cache Provider and four Fluid Cache Client would have had same capacity for Fluid Cache pool and all eight servers could have taken advantage of Fluid Cache However the chosen configuration for the technical white paper provides better performance the because VDI application caching load is unforming distributed among all the available servers
13 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 3 Infrastructure Set-up for VDI Solution
1 Enterprise Manager Console 2 Management and VDI Client Network 3 vSphere Servers hosting virtual desktops 4 Cache network switches (2)
5 SAN switch 6 Storage Center controllers (2) 7 Storage Center expansion enclosures (2) 8 Server hosting VDI infrastructure VMs
(Server 1) (Server 2)
14 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
4 Solution configuration This section provides information about the solution configuration and test setup for hosting Horizon View
virtual desktops including infrastructure components networking and storage subsystems
41 Host design considerations The entire VDI solution was installed in two vSphere server clusters The clusters included
Figure 4 vSphere server clusters
Infrastructure Cluster Two Dell PowerEdge R720 servers hosting VMs for Active Directory
services VMware vCenter 55 server Horizon View Connection server (primary and secondary)
View Composer server Microsoft Windows Server 2012 R2 based file server and SQL Server 2012
R2
View Client Cluster Eight Dell PowerEdge R720 servers hosting the virtual desktops Each server
had
o 2times10 core Intel Xeon CPU E5-2690v2 300GHz
o 256 GB RAM
o 1times350 GB Dell Express Flash PCIe SSD
o 1timesMellanox Connect ndash X3 card
o 1timesDual-port Broadcom NetXtreme II BCM57810 10 Gigabit NIC
o 1timesQuad-port Broadcom NetXtreme BCM5720 Gigabit NIC
Along with the other servers the above servers 40 LoginVSI launcher VMs were used to generate VDI
workload They can be hosted by two PowerEdge R720 servers or equivalent for VDI load generation
purposes
15 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
42 Network design considerations Figure 5 here shows the network layout of one of the eight PowerEdge R720 servers with vSphere 55
installed
Figure 5 vSphere host network configuration
Three network switches are used in the Fluid Cache for VDI implementation One Force10 S55 1 GB switch
for all management traffic and VDI traffic The management traffic includes hosts and vSphere
management Compellent storage management and so on The networks are segregated by using VLANs
to separate different types of traffic
One Dell Force10 S4810 10 GB switch is used for Fluid Cache cache network which supports all the traffic
between cache layer on eight VDI VM hosts Another Force10 S4810 10 GB switch is used for iSCSI
network between infrastructure hosts VDI VM hosts and Compellent SC8000
Appendix B has extended information on the vSwitch configuration for each vSphere host
16 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
43 Dell Compellent SC8000 storage array configurations The storage used to host the virtual desktops was a Dell Compellent SC8000 array running Storage Center
Operating System (SCOS) 65 All two front-end ports were 10 GB iSCSI and all two back-end ports were
six GB serial-attached SCSI (SAS) The array used two external enclosures with Write Intensive (WI) SSDs
comprising Tier 1 and 15K SAS HDDs comprising Tier 2 for performance Also 72 NL-SAS drives were
used in Tier 3 to provide capacity for user data Table 2 summarizes the storage hardware configuration
Table 2 Storage hardware components
Storage role Type Qty Description
Controllers SC8000 2 System Center Operating System (SCOS) 65
Enclosures External 2 24 bay ndash 25rdquo disk drive enclosure
Ports Ethernet ndash 10 Gbps 2 Front end host connectivity
SAS - 6 Gbps 4 Back end drive connectivity
Drives 400 GB WI SSD 12 11 active with 1 hot spare
300 GB 15K SAS HDD
21 20 active with 1 hot spare
4 TB 72K NL-SAS HDD
12 11 active with 1 hot spare
The volumes created to host the virtual desktops took advantage of the Compellent Dynamic Capacity
technology for efficient capacity allocation Table 3 lists the volume layout used for the infrastructure
functions including user data
Table 3 Volume layout for hosting infrastructure components and user data
Volume name Size Purpose
Infrastructure 500 GB Storage for Active Directory SQL Server vCenter Server View Connection Server View Composer and File Server
UserSpace 2 TB Storage for User profiles and folder redirection space (Average 25 GB per user)
Along with the infrastructure volumes the storage array also provided shared storage for hosting the
virtual desktops The volume layout used for configuring the base image (View Composer Replica) and VDI
volumes on the array is shown in Table 4
17 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 4 Dell Storage PS4210XS layout for volumes hosting virtual desktops
Volume name Size Purpose
View-Replicas1 and 2 100 GB each Storage for base image for VDI deployment
VDI-Images1 through 8 500 GB each Storage for VDI VMs in VDI Cluster Each volume hosted 100 desktops
44 vSphere host network configuration VMware vSphere 55 hypervisor was installed on all servers The network configuration on each of those
hosts is described here Each vSphere host was configured with five virtual switches vSwitch0 vSwitch1
vSwitch2 vSwitch3 and vSwitch4 to separate different types of traffic on the system
Table 5 vSwitch configuration in vSphere hosts
vSwitch Description
vSwitch0 Management Network
vSwitch1 and vSwitch2 iSCSI SAN
vSwitch3 Fluid Cache VLAN
vSwitch4 VDI LAN
For additional information about individual vSwitch configuration refer to Appendix B in the Dell technical
white paper
45 Horizon view configuration Horizon View 60 was installed by using the documentation provided by VMware
Horizon View 601 installation documentation
httpswwwvmwarecomsupportpubsview_pubshtml
Table 6 Specific configuration used in the tests
Purpose Count Type Memory CPU
Horizon View Connection Servers
2 VM 16 GB 8nos
View Composer Server 1 VM 8 GB 8nos
18 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
46 Windows 7 VM configuration Following the guidelines from VMware and Login VSI the Windows 7 base image was generated based on
a generic base VM with the following properties
VMware Virtual Hardware version 8
Two virtual CPU
3 GB RAM with 15GB reserved
25 GB virtual hard drive
One virtual NIC connected to the VDI network
Windows 7 64-bit OS
Also the base image was customized by using the VMware Horizon with View Optimization Guide for
Windows 7 and Windows 8 available at this location httpwwwvmwarecomfilespdfVMware-View-
OptimizationGuideWindows7-ENpdf
19 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
5 Horizon view test methodology This section outlines the test objectives along with the test tools and criteria used to determine the
optimal virtual desktop density and best practices for deploying Horizon View on Dell Fluid Cache for SAN
for high IOPS type VDI environment
51 Test objectives As noted in Section 11 the test objectives were
Develop an optimal end-to-end infrastructure design for a Horizon View and vSpherendashbased high
user type of VDI solution deployed by using the Fluid Cache Compellent storage PowerEdge
servers and Dell Networking switches
Determine the performance at every layer of the VDI solution stack under high IOPS workload For
example desktops generating 80ndash90 IOPSVM at steady state
Determine the performance impact of peak IO activity such as boot and login storms
52 Test tools All tests were conducted by using Login VSI 40 as the workload generator and user experience analyzer
tool Login VSI is a benchmarking tool to measure the performance and scalability of centralized desktop
environments such as Server Based Computing (SBC) and VDI
Note More information can be found at the Login VSI website httpwwwloginvsicom
In addition to Login VSI Iometer is used in desktop VMs to simulate high IOPS conditions Iometer is
invoked in desktop VMs by using custom scripting of Login VSI workloads
Note More information can be found at the Iometer project website httpwwwiometerorg
521 Load generation First the ldquoMediumrdquo workload from Login VSI was used to simulate the standard user workload The
characteristics of the Medium workload are
Up to five applications are started simultaneously
Applications include Microsoft Internet Explorer Microsoft Word Microsoft Excel Microsoft
PowerPoint PDF reader 7-Zip compression software Movie player and FreeMind
After a session is started the medium workload repeats approximately after every 48 minutes
During a loop the response time is measured after every 3ndash4 minutes
Idle time is about two minutes in each 48-minute loop
Type rate is approximately 160 milliseconds per character
After the test by using Login VSI Medium was complete tests were rerun with Login VSI Medium and
Iometer in desktop VMs to simulate high IOPS VDI workload While the Login VSI Medium generates 8ndash10
20 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
IOPSVM the latter method was able to generate 80ndash90 IOPSVM For these tests each VM in the Horizon
view pool is created with standard LoginVSI contents and applications Also Iometer is installed on each
VM After the user logs in a customized logon script starts the Iometer with required IO specification (icf
file)
522 Monitoring tools The following monitoring tools were used
Dell Compellent Enterprise Manager for monitoring Fluid Cache and Compellent SC8000 storage
array performance
VMware vCenter statistics for vSphere performance
Login VSI Analyzer for end user performance statistics
Detailed performance metrics were captured from the storage arrays hypervisors virtual desktops and
the load generators during the tests
53 Test criteria The primary focus of the tests is to validate the 800 desktop high IOPS type of VDI architecture with
acceptable user experience by using Fluid Cache for SAN VDI configurations involve many components at
different layers ndash application hypervisor server network and storage As a result multiple metrics need to
be captured at different layers to ensure that the environment is healthy and performing optimally and
appropriately for all users
The specific test criteria are described in the following sections
531 Storage capacity and IO latency The typical industry standard latency limit for storage disk IO is 10 milliseconds Maintaining this limit
ensures good user application response times when there are no other bottlenecks at the infrastructure
layer In addition Dell recommends to maintain a 10 percent spare disk space on the storage array for
optimal performance
532 System utilization at the hypervisor Even though the primary focus of these tests was storage characterization additional metrics at the
hypervisor infrastructure layer were defined to ensure solution consistency These were
CPU utilization on any vSphere server must not exceed 85 percent
Minimal memory ballooning on the VMs
Total network bandwidth utilization must not exceed 90 percent on any one link
TCPIP storage network retransmissions should be less than 05 percent
21 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
533 Virtual desktop user experience Login VSI Analyzer was also used to gather metrics on the user experience at the virtual desktop layer to
ensure that all the desktops had acceptable levels of application performance Login VSI uses the VSImax
parameter to determine the maximum number of sessions that can be obtained from a deployed solution
The calculation methodology used in VSImax is available here
httpwwwloginvsicomdocumentationindexphptitle=Analyzing_Results
534 Test configuration A single virtual desktop pool was configured by using the VMware Horizon View Administrator interface
Each pool was built from a Windows 7 base image The Windows 7 configuration information is available
in Section 46
Desktop pool properties
Automatic Desktop Pool
Users are assigned using Floating assignments
View Storage Accelerator is enabled for all hosts with a refresh period of seven days
800 desktops were deployed across eight hosts (100 desktops a host)
Replica images were stored on a separate volume
22 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
6 Test results and analysis This section presents the results from the different Horizon View VDI characterization tests and the key
findings from each test The testing was focused on the high IOPS workload profile
61 Test scenarios The following tests were conducted to gather results and analysis on the solution stack
1 Boot storm Boot storms represent the worst-case scenario where many virtual desktops are
turned on at the same time and they all contend for the system resources simultaneously This test
was used to evaluate if the storage array hosting the desktops was capable of handling huge
variation in storage IO without causing significant impact on other services
2 Login storm Login storms also represent a high IOPS situation where many users are logging in to
their virtual desktops at the beginning of a workday or a shift In this test all the desktops were
pre-booted and left in an idle state for more than 20 minutes to let their IO settle before running
the Login VSI Medium workload to simulate users logging in to their virtual desktops
3 Steady state workload for standard users with normal IOPS After the login storm for the previous
test was completed the Login VSI Medium workload was allowed to run for at least one hour to
simulate the real-world scenario of users performing their daily tasks The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
4 Steady state workload for users with high IOPS The previous test was repeated with the Login
VSI Medium workload and Iometer scripts in desktop VMs as described in Section 521 to simulate
real-world heavy users performing their daily tasks with high IOPS The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
The following sections provide results from the boot storm login storm and steady state testing for the
Fluid Cache for SAN based VDI solution
23 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
62 Boot storm IO To simulate a boot storm the virtual desktops were reset simultaneously from the VMware vSphere client
Figure 6 shows the IO pattern on the Fluid Cache for the boot storm
Figure 6 SAN HQ data showing boot storm performance with Fluid Cache array
With 800 desktops the boot storm generated about 115000 total IOPS with a majority of them being
write operations All desktops were available for use in less than four minutes
24 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
63 Login storm and steady state for standard users (LoginVSI
Medium) Login VSI was programmed to start 800 virtual desktops over a period of about 60 minutes after pre-
booting the virtual desktops The peak IOPS during the login storm observed by the vSphere servers
hosting the desktops was about 6500 IOPS (8ndash10 IOPS a VM)
In a standard user environment login storms generate significantly more write IOPS than a boot storm or
steady state because of multiple factors such as
User profile activity
Starting operating system services on the desktop
First start of applications
After a virtual desktop has achieved a steady state after user login the Windows 7 OS has cached
applications in memory and does not need to access storage each time the application is started This
leads to lesser IOPS during the steady state Figure 7 here shows the various IO characteristics during the
login storm and steady state of these tests
25 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 7 IOPS and Cache Hit for the standard user test
On the Fluid Cache layer the maximum IOPS reached 6500 with cache-hit reaching 100 percent and
read-hit around 95 percent As shown in the Figure 8 here the throughput peaked at 98 MBps with a low
latency of less than 2 msec
26 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 8 Throughput and Latency for the standard user test
631 Server host performance During the login storm and steady state of the test the vSphere host CPU memory network and storage
performance were measured on all the servers that hosted the virtual desktops The performance of one
such vSphere server is given here The other vSphere servers had similar performance characteristics
Statistics for the vSphere hosts were captured by using VMware vCenter Server The figures here show the
CPU memory and network utilization for boot storm login storm and steady state of one of the vSphere
servers hosting the virtual desktops The results shown here are for a test run with 800 no standard user
desktops in the desktop pool
27 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 9 Average CPU performance per core on one vSphere host during login storm and steady state
Figure 10 Disk space usage during login storm and steady state
0
10
20
30
40
50
60
70
80
90
100
1020 1045 1110 1135 1200 1225
Per
cen
t
Time
CPU Performance
0
50
100
150
200
250
300
1020 1040 1100 1120 1140 1200 1220
GB
Time
Memory Performance
Granted Swap used Shared common
28 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 11 Overall network performance during login storm and steady state
Figure 12 Storage adapter performance during login storm and steady state
0
10000
20000
30000
40000
50000
60000
70000
1020 1045 1110 1135 1200 1225
kBp
s
Time
Network Performance
0
05
1
15
2
25
1020 1045 1110 1135 1200 1225
mSe
c
Time
Storage adaptor performance
29 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
The key observations from the statistics were
CPU utilization was less than the 85 percent threshold throughout the test
Active disk space usage was about 80 percent during the boost storm and about 60 percent
during login storm and steady state There was minimal-or no memory ballooning observed
Network utilization was about 45 percent which included all the networks such as iSCSI SAN VDI
LAN Management LAN and vMotion LAN
Average read- and write latencies at the storage adapter level were very close to the observed
latencies in Fluid Cache 2 msec
632 Monitoring user experience Figure 13 here shows the response time as experienced by each user as calculated by Login VSI The graph
clearly shows that the VSImax (Dynamic) value has not been reached and there were non-responsive or
inactive sessions This means that the array is capable of supporting the 1000 desktops and all users have
acceptable response times for applications that the user is has started
Figure 13 Login VSI user experience monitoring for 800 standard user desktops
30 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
633 Standard user test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SANndashbased VDI solution is able to host 800 virtual desktops and support
a standard user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only operations and
less than 2 percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to handle this login storm easily with low latency mdash it delivered the required 6500 IOPS with less
than 2 milliseconds of write latency with a 99 percent write VDI IO workload
64 Login storm and steady state with high IOPS (LoginVSI Medium +
Iometer) As mentioned earlier Iometer was used in desktop VMs alongside the Login VSI Medium workload to
simulate high IOPS type of VDI environment To mimic actual VDI workload profile the following Iometer
profile was used
20 KB block size 80 percent write 75 percent random with 25 msec burst delay
Figure 14 here shows the various IO characteristics during the login storm and steady state of these tests
Figure 14 IOPS and Cache Hit for the high IOPS test
On the Fluid Cache layer the maximum IOPS reached was approximately 72000 (or 90 IOPSVM) with
cache write-hit 100 percent and read-hit around 95 percent As shown in the Figure 15 the throughput
peaked at greater than 900 MBps with a peak latency of approximately 75 msec
31 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 15 Throughput and Latency for the high IOPS test
32 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
641 Server host performance Similar to the standard user test statistics for the vSphere hosts were captured by using VMware vCenter
Server during the high IOPS (heavy user) test also There are no significant differences in CPU disk space
and network utilization between standard users and heavy users The storage adapter latency is also
showing similar on hosts and observed on Fluid Cache
642 User experience monitoring Figure 16 here shows the response time as experienced by each user as calculated by Login VSI for the
heavy user test The graph shows that the VSImax (Dynamic) value was 796 indicating that the solution is
capable of supporting the 800 user high IOPS desktops with 90 IOPSVM
Figure 16 Login VSI user experience monitoring for 800 user high IOPS desktops
33 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
643 High IOPS (heavy user) test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SAN based VDI solution is able to host 800 virtual desktops and support a
high user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only and less than 2
percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to easily handle this login storm with low latency Subsequently it was able to handle 72000 IOPS
at high IOPS steady state with 90 IOPSVM with a maximum of 75 msec latency
34 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
7 Best practices This section provides the best practices derived from the testing and analysis in Section 6
71 Virtual Desktop Infrastructure This section provides best practices for the implementation of VDI using Dell Fluid Cache for SAN
711 Implement roaming profiles and folder redirection Dell recommends that all users in the VDI environment be configured with roaming profiles and folder
redirection This preserves user profiles and user data across boots while using non-persistent virtual
desktops
Also Dell recommends to use a high performance file service to provide the profile and folder redirection
A separate array may be used to host these volumes for best performance
712 Boot and login storm considerations Section 62 demonstrated the Fluid Cache for SAN performance under boot storm To avoid any potential
IO bursts because of boot storm and degraded user experience and performances Dell recommends that
all or portion of desktops be prebooted Connection brokers such as VMware Horizon View provide the
functionality to configure number of standby desktops
713 Windows 7 master image for desktop VMs Dell recommends that the operating system be customized in order to provide the best performance in a
VDI environment This includes disabling some services which may not be required This can improve
performance for the end user VMware has a specific set of recommendations and settings for Windows 7
and Windows 8 that allow for faster logins quicker screen refreshes and generally better performance
The VMware recommendations for Windows 7 and Windows 8 image optimization can be found here
httpwwwvmwarecomresourcestechresources10157
714 VDI Management infrastructure recommendations Dell recommends to have redundancy and load balancing for all VDI management services in the case of
VMware Horizon View solution as tested here the vSphere Server VMware Horizon View Servers and SQL
Servers Ideally these should be running on clustered hosts with VMware vSphere DRS (distributed
resource scheduler) and HA (high availability) enabled
72 Server host The vSphere servers hosting the infrastructure service providers and the virtual desktops are
recommended to be configured as follows
35 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Follow VMware and Dell best practices for installing and configuring vSphere
Separate virtual switches to segregate iSCSI SAN traffic VDI traffic vMotion traffic and Management
network traffic
Each network path must be assigned to a minimum of two physical NICs for high availability
VMware Knowledge Base article about best practices for installing vSphere 55
httpkbvmwarecomkb2052329
73 Network layer Dell recommends that at least two physical NICs on each vSphere server be dedicated to the VDI network
Use VLANs to segregate different types of network traffic on the same physical network In this case Dell
recommends to separate the infrastructure vMotion and VDI LAN traffic in to separate VLANs
Do not use VLANs to segregate iSCSI SAN and Fluide Cache traffic It is required that SAN and Cache traffic
be on separate dedicated physical network to provide the best performance
Virtual switches in vSphere have a default limit of 120 ports If the number of virtual desktops on each host
exceeds the available ports vSwitch properties should be changed to support the required number of
virtual desktops This change requires a restart of the host vSphere server
On iSCSI SAN switches Spanning tree must be disabled on switch ports connected to end devices for
server and storage ports The PortFast setting must be enabled in the switch configuration for these ports
Jumbo frames and Flow control (if the NICs support it) should be enabled for all components of the iSCSI
network
More information about configuring Dell Networking switches for use with Dell Storage iSCSI SANs is
available here
httpencommunitydellcomtechcenterstoragewwiki4250switch-configuration-guides-by-sisaspx
74 Storage The Dell SC storage arrays combined with Fluid Cache is an excellent platform for providing cost-effective
performance in VDI environments
Fluid Cache for SAN extends the power of Compellent intelligent data placement from the SAN to the
server By providing a single infrastructure for data at both high- and low ends of the performance
spectrum Fluid Cache for SAN with Storage Center 65 array software eliminates the tradeoffs between
server performance and full-featured SAN benefits such as reliability manageability and data protection
Dell recommends to have separate volumes for base image and virtual desktops This enables better
manageability of the volumes easier performance monitoring and allows easy future growth
Dell recommends to use a separate high performance file service to provide file shares for roaming
profiles and user shares
36 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
8 Conclusion The technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed by using a Horizon View VDI platform leveraging Dell Fluid Cache for SAN The storage IO
characteristics under various VDI workload scenarios (boot storm login storm and steady state) along
with performance characteristics throughout the VDI stack (for example vSphere server performance and
user experience) demonstrate the optimal configuration of the infrastructure used for this VDI
deployment For more information about Fluid Cache contact your Dell account manager
37 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
A Horizon view solution configuration
Table 7 Hardware components
Hardware components Description
Virtual Desktops 4 timesDell PowerEdge R720 Servers (Fluid Cache Providers)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
2times350 GB Dell Express Flash PCIe SSDs
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
4 x Dell PowerEdge R720 Servers (Fluid Cache Clients)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55 U2 on all R720 servers Windows 7 (64 Bit) VMs
Infrastructure Servers 2 x Dell PowerEdge R720 servers
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
96 GB RAM
2times300 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55U2 on all R720 servers VMs are loaded with Microsoft Windows 2008 R2
Active Directory
VMware Horizon View 60 Server 1
VMware Horizon View 60 Server 2
VMware vCenter Server 55 update 2
VMware Horizon View Composer
SQL Server
File Server
Login VSI Launchers 8 x Dell PowerEdge M610 servers
2timesIntelreg Xeonreg E-5503 200 GHz Processors
16 GB RAM
4times146 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57711 10GbE NIC
ESXi 51 installed on all R810 servers VMs are loaded with Microsoft Windows 7 64bit Each VM supports up to 30 Login VSI launcher sessions
38 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Network Management VDI LAN
1timesDell Force10 S55 1Gb Ethernet Switch
iSCSI SAN
1timesDell Force10 S4810 10Gb Ethernet Switch
Cache network
1timesDell Force10 S4810 10Gb Ethernet Switch
One Force10 S4810 switch might suffice for all the cache iSCSI SAN VDI LAN and management traffic
Storage 2timesDell Compellent SC8000 controllers 4times6Gb SAS 4-port PCI-E Full-height cards for back-end connectivity 2times10Gb iSCSI 2 port PCI-E Low-profile IO cards for front end connectivity 1timesDell Compellent SC200 disk enclosures 12times4TB NL-SAS 6Gb 72K 35rdquo drives
User Data Infrastructure VMs Virtual Desktops
Performance Monitoring
Dell Compellent Enterprise Manager Dell Fluid Cache for SAN performance monitoring tool () vCenter Performance monitoring Liquidware Stratusphere UX
Performance monitoring on Compellent arrays Fluid Cache performance monitoring Performance monitoring and capture at the ESXi host User experience monitoring on the virtual desktop
39 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 8 Software components
Software components Description Version
Dell Fluid Cache for SAN 20
Dell Compellent Storage Center 64
Dell Compellent Enterprise Manager 64
VMware Horizon View Server 60
VMware Horizon View Composer 60
VMware Horizon View Agent 60
VMware Horizon View Client 64-bit 60
VMware ESXi Hypervisor 55 U2
VMware vCenter Server 55 U2
Microsoft SQL Server 2008R2 Enterprise x64 105016001
Client VM OS Microsoft Windows 7 Enterprise x64 SP1
Management VM OS Microsoft Windows Server 2008 Enterprise R2 x64 SP1
Microsoft Office MS office 2010 Standard Service Pack 1
Login VSI Version 40
Iometer 20060727
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
6 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
1 Introduction Desktop virtualization platforms such as VMware Horizon View 60 (Horizon View) can provide
organizations with significant cost savings streamlined implementation and ease of desktop
management In order to achieve these VDI benefits and to ensure optimal user experience the end-to-
end infrastructure design and sizing considerations need to be addressed carefully While VDI workloads
for task and knowledge workers are correctly understood by using many cost-effective solutions that are
available the high IOPS 800-user VDI use cases are addressed less often because current solutions
typically do not meet the stringent performance- and capacity requirements of these use cases in an
economically sensible manner
The goal of this technical white paper is to present the results of a series of storage IO performance tests
and provide the optimal end-to-end infrastructure design for high IOPS 800-user type VDI environments
leveraging Dell Fluid Cache for SAN Dell Compellent SAN storage arrays Dell PowerEdge servers and Dell
Networking switches
11 Objectives The primary objectives of the tests conducted for this technical white paper are
Develop an optimal end-to-end infrastructure design for a Horizon View and vSphere-based
heavy user type VDI solution deployed by using the Fluid Cache Compellent storage PowerEdge
servers and Dell Networking switches
Determine the performance at every layer of the VDI solution stack under high IOPS workload For
example desktops generating 80ndash90 IOPSVM at steady state
Determine the performance impact of peak IO activity such as boot and login storms
The test infrastructure used for the tests included
VMware Horizon View 60
VMware vSphere 55 hypervisor
Dell PowerEdge R720 servers with Dell Express PCIe SSDs
Dell Networking S4810 switches
Dell Compellent SC8000 storage array
111 Audience This technical white paper is intended for solution architects storage network engineers system
administrators and IT managers who need to understand about designing properly sizing and deploying
Horizon View-based VDI solutions by using Dell infra design properly sizing and deploying Horizon View-
based VDI solutions by using Dell infrastructure It is expected that the reader has a working knowledge of
the Horizon View architecture vSphere system administration iSCSI SAN network design and Dell
Compellent SAN operation
7 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
2 Dell Fluid Cache for SAN and VDI Dell Fluid Cache for SAN utilizes direct-attached Dell PowerEdge Express Flash NVMe PCIe SSDs and
remote direct memory access (RDMA) networking capabilities to create a clustered caching pool for
improved storage workload performance Applications write directly to the cache pool the
acknowledgement is sent back to the application and in the background the IO is flushed to the external
storage array Data is copied in to the cache pool when it is accessed (read) by application and is available
from the cache pool for reread operations Also data that is written into the cache pool by the application
is then available for reread operations from the application A high-speed link to other cache nodes in the
Fluid Cache for SAN pool allows the data to remain highly available by replicating blocks of data even if a
single node in cache pool stops working Fluid Cache for SAN provides a single management interface and
provides other capabilities such as cache-aware snapshots and replication and compression
Figure 1 shows an example environment highlighting how Fluid Cache for SAN communicates between
server and storage Three nodes are required to run Dell Fluid Cache for SAN software Two of these three
nodes are required to have a minimum of one Dell PowerEdge Express Flash NVMe PCIe SSD each and
the network for private cache network is based on the low-latency RDMA protocol The RDMA network
handles the cache pool communication between the nodes Creation and management of the Fluid
Cache cluster are accomplished by using the Dell Compellent Enterprise Manager software through
automatic cache server discovery
Figure 1 Dell Fluid Cache for SAN communication
8 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Fluid Cache for SAN is an ideal solution for high IOPS type VDI environment with highly write-intensive
workloads because it provides extremely fast and low-latency server-side write back caching Because
writes are mirrored across high-speed network and later destaged to the SAN with significant write
coalescing this solution can sustain significantly higher IOPSVM than an external hybrid or all-flash array
ndashbased solution could
9 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
3 Solution architecture The overall architecture of the VDI solution for the high IOPS environment is shown in the figure here
Figure 2 VDI solution architecture
31 Software Horizon view Horizon View is a VDI solution that includes a complete suite of tools for delivering desktops as a secure
and managed service from a centralized infrastructure A Horizon View infrastructure consists of many
different software network and hardware layer components This section presents an overview of the key
Horizon View components and technologies that are critical for successful design and deployment of the
VDI environment
10 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
311 Horizon view components A functional list of Horizon View components used in this solution is given in the table here
Table 1 Horizon View components
Component Description
Client Devices Personal computing devices used by end users to run the Horizon View Client These can include special end-point devices such as Dell Wyse end points mobile phones and PCs
Horizon View Connection Server
A software service that acts as a broker for client connections by authenticating and then directing the incoming user requests to the appropriate virtual desktop physical desktop or terminal server
Horizon View Client Software that is used to access the Horizon View desktops
Horizon View Agent A service that runs on all systems used as sources for Horizon View desktops and facilitates network communication between the Horizon View clients and the Horizon View server
Horizon View Administrator
A web-based administration platform for the Horizon View infrastructure components
vCenterreg Server Central administration platform for configuring provisioning and managing VMware virtualized data centers
Horizon View Composer
A service running with Horizon View servers used to create pools of virtual desktops from a shared-base image to reduce storage capacity requirements
312 Virtual desktops Virtual desktops can be classified in to two major categories persistent and non-persistent
Persistent desktop environment All configuration and personalization on the assigned desktop is kept for
the user-between sessions When using persistent desktops an administrator usually has to provision
additional storage along with other administrative requirements such as patching and upgrading of
individual desktops
Non-persistent desktop environment Users are dynamically assigned virtual desktop VMs from a pool of
resources during login This type of virtual desktop does not retain any information between sessions At
logoff all changes are simply discarded and the virtual desktop is returned to the original state Patching
and upgrading non-persistent desktops requires only making the change to the base image and refreshing
or recomposing the virtual desktop pool Thus these desktops are much easier to manage but lack the
potential for persistent user customization
11 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
313 Horizon view desktop pools A desktop pool is a term VMware uses to describe a collection of desktops that are managed as a single
entity by the Horizon View Administrator interface Horizon View desktop pools allow administrators to
group users depending on the type of service the user requires There are two types of pools ndash Automated
and Manual
In Horizon View an Automated Pool is a collection of VMs cloned from a base template while a Manual
pool is created by the Horizon View Manager from existing desktop sources physical or virtual For each
desktop in the Manual pool the administrator selects a desktop source to deliver Horizon View access to
the clients
VMware View Personas profile management features can be used to achieve persistent desktop-like
behavior on non-persistent desktops By using these features an administrator can design a user account
where the configuration settings are written to a remote profile that is stored separately from the virtual
desktop image files This reduces the need for additional management on individual virtual desktops while
still providing a customized user experience
314 Using linked clones Significant storage space savings and increased efficiencies in desktop VM provisioning and administration
are possible when using VMware-linked clones A linked clone is a duplicate VM that shares the same base
image with the original VM but has separate differential data disks to track the differences from the
original one Each linked clone functions as an independent desktop VM with its own unique identity
Because linked clones share the same base image they consume significantly less storage disk space than
a set of completely independent VM images Temporary system data and other data unique to each linked
clone desktop VM are written to separate differential data storage and these temporary changes are
discarded during restart andor user logoff Persistent data such as user profiles applications and user
data can be optionally redirected to a CIFS share With this model software maintenance updates
antivirus remediation and patches need to be applied only on the base image These base image changes
automatically take effect on all linked clones without affecting any user settings and data
To configure linked clones the administrator creates a snapshot of a parent VM image with the required
OS settings and software installed Horizon View Composer first creates a full replica (clone) of the parent
VM and then uses this replica to create linked clones The replica can be placed on the same data store as
the linked clones or on a separate data store
More information about configuring linked clones can be found in the ldquoCreating Desktop Poolsrdquo section of
the VMware Horizon View Online Library here
315 Hypervisor platform VMware vSphere 55 VMware vSphere 55 is the enterprise virtualization platform used for building VDI and cloud
infrastructures VMware vSphere 55 includes three major layers virtualization management and interface
The virtualization layer includes infrastructure and application services The management layer is central
12 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
for configuring provisioning and managing virtualized environments The interface layer includes the
vSphere client and the vSphere web client
Throughout the solution all VMware and Microsoft best practices and prerequisites for core services were
used (NTP DNS Active Directory and others)
32 Hardware Dell infrastructure Figure 3 shows the design of the infrastructure for the Horizon Viewndashbased high IOPS type VDI
deployment that leverages Fluid Cache
An eight-node vSphere server cluster is used to host the virtual desktops Each of these server nodes has a
direct-attached PCIe SSD that is added to the Fluid Cache pool thus making each server a Fluid Cache
Provider (a server contributing to the Fluid Cache capacity) The eight PCIe SSDs were distributed among
all the servers to better balance the load on the Fluid Cache server Fluid Cache server1 These servers
were connected by using a private caching network to provide the Fluid Cache functionality Also the
servers were connected through a separate managementVDI client network and a 10 GB Ethernet iSCSI
SAN network
Another two-node vSphere server cluster is used to host the VDI infrastructure VMs such as vCenter
server View Connection server View Composer server SQL Server and Active Directory etc These
infrastructure servers were connected to the management network and the iSCSI SAN network
The Compellent storage array for the solution has two controllers and a mix of Write Intensive (WI) SSDs
15K SAS HDDs and 72K NL-SAS HDDs to provide the optimal performance and capacity needed for the
solution
Two switches are stacked together for different networks to provide redundancy in the networking layer
Ideally 40 GB Ethernet switches are recommended for the cache network While 1 GB Ethernet switches
can be used for management network it is better to use 10 GB Ethernet switches combining management
and VDI client networks The same 10 GB Ethernet switches can be used for iSCSI SAN also (with different
network traffic segmented by VLANs) provided they have adequate bandwidth needed for the specific VDI
deployment
Information about how this reference architecture was developed ensuring the optimal utilization across
the servers switches and storage arrays is discussed later in the following sections of this technical white
paper
1 Fluid Cache does not require all servers to be a Fluid Cache Provider For example in this case four
servers could have two PCIe SSDs each This configuration with four Fluid Cache Provider and four Fluid Cache Client would have had same capacity for Fluid Cache pool and all eight servers could have taken advantage of Fluid Cache However the chosen configuration for the technical white paper provides better performance the because VDI application caching load is unforming distributed among all the available servers
13 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 3 Infrastructure Set-up for VDI Solution
1 Enterprise Manager Console 2 Management and VDI Client Network 3 vSphere Servers hosting virtual desktops 4 Cache network switches (2)
5 SAN switch 6 Storage Center controllers (2) 7 Storage Center expansion enclosures (2) 8 Server hosting VDI infrastructure VMs
(Server 1) (Server 2)
14 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
4 Solution configuration This section provides information about the solution configuration and test setup for hosting Horizon View
virtual desktops including infrastructure components networking and storage subsystems
41 Host design considerations The entire VDI solution was installed in two vSphere server clusters The clusters included
Figure 4 vSphere server clusters
Infrastructure Cluster Two Dell PowerEdge R720 servers hosting VMs for Active Directory
services VMware vCenter 55 server Horizon View Connection server (primary and secondary)
View Composer server Microsoft Windows Server 2012 R2 based file server and SQL Server 2012
R2
View Client Cluster Eight Dell PowerEdge R720 servers hosting the virtual desktops Each server
had
o 2times10 core Intel Xeon CPU E5-2690v2 300GHz
o 256 GB RAM
o 1times350 GB Dell Express Flash PCIe SSD
o 1timesMellanox Connect ndash X3 card
o 1timesDual-port Broadcom NetXtreme II BCM57810 10 Gigabit NIC
o 1timesQuad-port Broadcom NetXtreme BCM5720 Gigabit NIC
Along with the other servers the above servers 40 LoginVSI launcher VMs were used to generate VDI
workload They can be hosted by two PowerEdge R720 servers or equivalent for VDI load generation
purposes
15 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
42 Network design considerations Figure 5 here shows the network layout of one of the eight PowerEdge R720 servers with vSphere 55
installed
Figure 5 vSphere host network configuration
Three network switches are used in the Fluid Cache for VDI implementation One Force10 S55 1 GB switch
for all management traffic and VDI traffic The management traffic includes hosts and vSphere
management Compellent storage management and so on The networks are segregated by using VLANs
to separate different types of traffic
One Dell Force10 S4810 10 GB switch is used for Fluid Cache cache network which supports all the traffic
between cache layer on eight VDI VM hosts Another Force10 S4810 10 GB switch is used for iSCSI
network between infrastructure hosts VDI VM hosts and Compellent SC8000
Appendix B has extended information on the vSwitch configuration for each vSphere host
16 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
43 Dell Compellent SC8000 storage array configurations The storage used to host the virtual desktops was a Dell Compellent SC8000 array running Storage Center
Operating System (SCOS) 65 All two front-end ports were 10 GB iSCSI and all two back-end ports were
six GB serial-attached SCSI (SAS) The array used two external enclosures with Write Intensive (WI) SSDs
comprising Tier 1 and 15K SAS HDDs comprising Tier 2 for performance Also 72 NL-SAS drives were
used in Tier 3 to provide capacity for user data Table 2 summarizes the storage hardware configuration
Table 2 Storage hardware components
Storage role Type Qty Description
Controllers SC8000 2 System Center Operating System (SCOS) 65
Enclosures External 2 24 bay ndash 25rdquo disk drive enclosure
Ports Ethernet ndash 10 Gbps 2 Front end host connectivity
SAS - 6 Gbps 4 Back end drive connectivity
Drives 400 GB WI SSD 12 11 active with 1 hot spare
300 GB 15K SAS HDD
21 20 active with 1 hot spare
4 TB 72K NL-SAS HDD
12 11 active with 1 hot spare
The volumes created to host the virtual desktops took advantage of the Compellent Dynamic Capacity
technology for efficient capacity allocation Table 3 lists the volume layout used for the infrastructure
functions including user data
Table 3 Volume layout for hosting infrastructure components and user data
Volume name Size Purpose
Infrastructure 500 GB Storage for Active Directory SQL Server vCenter Server View Connection Server View Composer and File Server
UserSpace 2 TB Storage for User profiles and folder redirection space (Average 25 GB per user)
Along with the infrastructure volumes the storage array also provided shared storage for hosting the
virtual desktops The volume layout used for configuring the base image (View Composer Replica) and VDI
volumes on the array is shown in Table 4
17 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 4 Dell Storage PS4210XS layout for volumes hosting virtual desktops
Volume name Size Purpose
View-Replicas1 and 2 100 GB each Storage for base image for VDI deployment
VDI-Images1 through 8 500 GB each Storage for VDI VMs in VDI Cluster Each volume hosted 100 desktops
44 vSphere host network configuration VMware vSphere 55 hypervisor was installed on all servers The network configuration on each of those
hosts is described here Each vSphere host was configured with five virtual switches vSwitch0 vSwitch1
vSwitch2 vSwitch3 and vSwitch4 to separate different types of traffic on the system
Table 5 vSwitch configuration in vSphere hosts
vSwitch Description
vSwitch0 Management Network
vSwitch1 and vSwitch2 iSCSI SAN
vSwitch3 Fluid Cache VLAN
vSwitch4 VDI LAN
For additional information about individual vSwitch configuration refer to Appendix B in the Dell technical
white paper
45 Horizon view configuration Horizon View 60 was installed by using the documentation provided by VMware
Horizon View 601 installation documentation
httpswwwvmwarecomsupportpubsview_pubshtml
Table 6 Specific configuration used in the tests
Purpose Count Type Memory CPU
Horizon View Connection Servers
2 VM 16 GB 8nos
View Composer Server 1 VM 8 GB 8nos
18 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
46 Windows 7 VM configuration Following the guidelines from VMware and Login VSI the Windows 7 base image was generated based on
a generic base VM with the following properties
VMware Virtual Hardware version 8
Two virtual CPU
3 GB RAM with 15GB reserved
25 GB virtual hard drive
One virtual NIC connected to the VDI network
Windows 7 64-bit OS
Also the base image was customized by using the VMware Horizon with View Optimization Guide for
Windows 7 and Windows 8 available at this location httpwwwvmwarecomfilespdfVMware-View-
OptimizationGuideWindows7-ENpdf
19 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
5 Horizon view test methodology This section outlines the test objectives along with the test tools and criteria used to determine the
optimal virtual desktop density and best practices for deploying Horizon View on Dell Fluid Cache for SAN
for high IOPS type VDI environment
51 Test objectives As noted in Section 11 the test objectives were
Develop an optimal end-to-end infrastructure design for a Horizon View and vSpherendashbased high
user type of VDI solution deployed by using the Fluid Cache Compellent storage PowerEdge
servers and Dell Networking switches
Determine the performance at every layer of the VDI solution stack under high IOPS workload For
example desktops generating 80ndash90 IOPSVM at steady state
Determine the performance impact of peak IO activity such as boot and login storms
52 Test tools All tests were conducted by using Login VSI 40 as the workload generator and user experience analyzer
tool Login VSI is a benchmarking tool to measure the performance and scalability of centralized desktop
environments such as Server Based Computing (SBC) and VDI
Note More information can be found at the Login VSI website httpwwwloginvsicom
In addition to Login VSI Iometer is used in desktop VMs to simulate high IOPS conditions Iometer is
invoked in desktop VMs by using custom scripting of Login VSI workloads
Note More information can be found at the Iometer project website httpwwwiometerorg
521 Load generation First the ldquoMediumrdquo workload from Login VSI was used to simulate the standard user workload The
characteristics of the Medium workload are
Up to five applications are started simultaneously
Applications include Microsoft Internet Explorer Microsoft Word Microsoft Excel Microsoft
PowerPoint PDF reader 7-Zip compression software Movie player and FreeMind
After a session is started the medium workload repeats approximately after every 48 minutes
During a loop the response time is measured after every 3ndash4 minutes
Idle time is about two minutes in each 48-minute loop
Type rate is approximately 160 milliseconds per character
After the test by using Login VSI Medium was complete tests were rerun with Login VSI Medium and
Iometer in desktop VMs to simulate high IOPS VDI workload While the Login VSI Medium generates 8ndash10
20 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
IOPSVM the latter method was able to generate 80ndash90 IOPSVM For these tests each VM in the Horizon
view pool is created with standard LoginVSI contents and applications Also Iometer is installed on each
VM After the user logs in a customized logon script starts the Iometer with required IO specification (icf
file)
522 Monitoring tools The following monitoring tools were used
Dell Compellent Enterprise Manager for monitoring Fluid Cache and Compellent SC8000 storage
array performance
VMware vCenter statistics for vSphere performance
Login VSI Analyzer for end user performance statistics
Detailed performance metrics were captured from the storage arrays hypervisors virtual desktops and
the load generators during the tests
53 Test criteria The primary focus of the tests is to validate the 800 desktop high IOPS type of VDI architecture with
acceptable user experience by using Fluid Cache for SAN VDI configurations involve many components at
different layers ndash application hypervisor server network and storage As a result multiple metrics need to
be captured at different layers to ensure that the environment is healthy and performing optimally and
appropriately for all users
The specific test criteria are described in the following sections
531 Storage capacity and IO latency The typical industry standard latency limit for storage disk IO is 10 milliseconds Maintaining this limit
ensures good user application response times when there are no other bottlenecks at the infrastructure
layer In addition Dell recommends to maintain a 10 percent spare disk space on the storage array for
optimal performance
532 System utilization at the hypervisor Even though the primary focus of these tests was storage characterization additional metrics at the
hypervisor infrastructure layer were defined to ensure solution consistency These were
CPU utilization on any vSphere server must not exceed 85 percent
Minimal memory ballooning on the VMs
Total network bandwidth utilization must not exceed 90 percent on any one link
TCPIP storage network retransmissions should be less than 05 percent
21 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
533 Virtual desktop user experience Login VSI Analyzer was also used to gather metrics on the user experience at the virtual desktop layer to
ensure that all the desktops had acceptable levels of application performance Login VSI uses the VSImax
parameter to determine the maximum number of sessions that can be obtained from a deployed solution
The calculation methodology used in VSImax is available here
httpwwwloginvsicomdocumentationindexphptitle=Analyzing_Results
534 Test configuration A single virtual desktop pool was configured by using the VMware Horizon View Administrator interface
Each pool was built from a Windows 7 base image The Windows 7 configuration information is available
in Section 46
Desktop pool properties
Automatic Desktop Pool
Users are assigned using Floating assignments
View Storage Accelerator is enabled for all hosts with a refresh period of seven days
800 desktops were deployed across eight hosts (100 desktops a host)
Replica images were stored on a separate volume
22 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
6 Test results and analysis This section presents the results from the different Horizon View VDI characterization tests and the key
findings from each test The testing was focused on the high IOPS workload profile
61 Test scenarios The following tests were conducted to gather results and analysis on the solution stack
1 Boot storm Boot storms represent the worst-case scenario where many virtual desktops are
turned on at the same time and they all contend for the system resources simultaneously This test
was used to evaluate if the storage array hosting the desktops was capable of handling huge
variation in storage IO without causing significant impact on other services
2 Login storm Login storms also represent a high IOPS situation where many users are logging in to
their virtual desktops at the beginning of a workday or a shift In this test all the desktops were
pre-booted and left in an idle state for more than 20 minutes to let their IO settle before running
the Login VSI Medium workload to simulate users logging in to their virtual desktops
3 Steady state workload for standard users with normal IOPS After the login storm for the previous
test was completed the Login VSI Medium workload was allowed to run for at least one hour to
simulate the real-world scenario of users performing their daily tasks The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
4 Steady state workload for users with high IOPS The previous test was repeated with the Login
VSI Medium workload and Iometer scripts in desktop VMs as described in Section 521 to simulate
real-world heavy users performing their daily tasks with high IOPS The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
The following sections provide results from the boot storm login storm and steady state testing for the
Fluid Cache for SAN based VDI solution
23 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
62 Boot storm IO To simulate a boot storm the virtual desktops were reset simultaneously from the VMware vSphere client
Figure 6 shows the IO pattern on the Fluid Cache for the boot storm
Figure 6 SAN HQ data showing boot storm performance with Fluid Cache array
With 800 desktops the boot storm generated about 115000 total IOPS with a majority of them being
write operations All desktops were available for use in less than four minutes
24 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
63 Login storm and steady state for standard users (LoginVSI
Medium) Login VSI was programmed to start 800 virtual desktops over a period of about 60 minutes after pre-
booting the virtual desktops The peak IOPS during the login storm observed by the vSphere servers
hosting the desktops was about 6500 IOPS (8ndash10 IOPS a VM)
In a standard user environment login storms generate significantly more write IOPS than a boot storm or
steady state because of multiple factors such as
User profile activity
Starting operating system services on the desktop
First start of applications
After a virtual desktop has achieved a steady state after user login the Windows 7 OS has cached
applications in memory and does not need to access storage each time the application is started This
leads to lesser IOPS during the steady state Figure 7 here shows the various IO characteristics during the
login storm and steady state of these tests
25 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 7 IOPS and Cache Hit for the standard user test
On the Fluid Cache layer the maximum IOPS reached 6500 with cache-hit reaching 100 percent and
read-hit around 95 percent As shown in the Figure 8 here the throughput peaked at 98 MBps with a low
latency of less than 2 msec
26 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 8 Throughput and Latency for the standard user test
631 Server host performance During the login storm and steady state of the test the vSphere host CPU memory network and storage
performance were measured on all the servers that hosted the virtual desktops The performance of one
such vSphere server is given here The other vSphere servers had similar performance characteristics
Statistics for the vSphere hosts were captured by using VMware vCenter Server The figures here show the
CPU memory and network utilization for boot storm login storm and steady state of one of the vSphere
servers hosting the virtual desktops The results shown here are for a test run with 800 no standard user
desktops in the desktop pool
27 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 9 Average CPU performance per core on one vSphere host during login storm and steady state
Figure 10 Disk space usage during login storm and steady state
0
10
20
30
40
50
60
70
80
90
100
1020 1045 1110 1135 1200 1225
Per
cen
t
Time
CPU Performance
0
50
100
150
200
250
300
1020 1040 1100 1120 1140 1200 1220
GB
Time
Memory Performance
Granted Swap used Shared common
28 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 11 Overall network performance during login storm and steady state
Figure 12 Storage adapter performance during login storm and steady state
0
10000
20000
30000
40000
50000
60000
70000
1020 1045 1110 1135 1200 1225
kBp
s
Time
Network Performance
0
05
1
15
2
25
1020 1045 1110 1135 1200 1225
mSe
c
Time
Storage adaptor performance
29 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
The key observations from the statistics were
CPU utilization was less than the 85 percent threshold throughout the test
Active disk space usage was about 80 percent during the boost storm and about 60 percent
during login storm and steady state There was minimal-or no memory ballooning observed
Network utilization was about 45 percent which included all the networks such as iSCSI SAN VDI
LAN Management LAN and vMotion LAN
Average read- and write latencies at the storage adapter level were very close to the observed
latencies in Fluid Cache 2 msec
632 Monitoring user experience Figure 13 here shows the response time as experienced by each user as calculated by Login VSI The graph
clearly shows that the VSImax (Dynamic) value has not been reached and there were non-responsive or
inactive sessions This means that the array is capable of supporting the 1000 desktops and all users have
acceptable response times for applications that the user is has started
Figure 13 Login VSI user experience monitoring for 800 standard user desktops
30 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
633 Standard user test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SANndashbased VDI solution is able to host 800 virtual desktops and support
a standard user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only operations and
less than 2 percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to handle this login storm easily with low latency mdash it delivered the required 6500 IOPS with less
than 2 milliseconds of write latency with a 99 percent write VDI IO workload
64 Login storm and steady state with high IOPS (LoginVSI Medium +
Iometer) As mentioned earlier Iometer was used in desktop VMs alongside the Login VSI Medium workload to
simulate high IOPS type of VDI environment To mimic actual VDI workload profile the following Iometer
profile was used
20 KB block size 80 percent write 75 percent random with 25 msec burst delay
Figure 14 here shows the various IO characteristics during the login storm and steady state of these tests
Figure 14 IOPS and Cache Hit for the high IOPS test
On the Fluid Cache layer the maximum IOPS reached was approximately 72000 (or 90 IOPSVM) with
cache write-hit 100 percent and read-hit around 95 percent As shown in the Figure 15 the throughput
peaked at greater than 900 MBps with a peak latency of approximately 75 msec
31 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 15 Throughput and Latency for the high IOPS test
32 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
641 Server host performance Similar to the standard user test statistics for the vSphere hosts were captured by using VMware vCenter
Server during the high IOPS (heavy user) test also There are no significant differences in CPU disk space
and network utilization between standard users and heavy users The storage adapter latency is also
showing similar on hosts and observed on Fluid Cache
642 User experience monitoring Figure 16 here shows the response time as experienced by each user as calculated by Login VSI for the
heavy user test The graph shows that the VSImax (Dynamic) value was 796 indicating that the solution is
capable of supporting the 800 user high IOPS desktops with 90 IOPSVM
Figure 16 Login VSI user experience monitoring for 800 user high IOPS desktops
33 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
643 High IOPS (heavy user) test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SAN based VDI solution is able to host 800 virtual desktops and support a
high user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only and less than 2
percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to easily handle this login storm with low latency Subsequently it was able to handle 72000 IOPS
at high IOPS steady state with 90 IOPSVM with a maximum of 75 msec latency
34 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
7 Best practices This section provides the best practices derived from the testing and analysis in Section 6
71 Virtual Desktop Infrastructure This section provides best practices for the implementation of VDI using Dell Fluid Cache for SAN
711 Implement roaming profiles and folder redirection Dell recommends that all users in the VDI environment be configured with roaming profiles and folder
redirection This preserves user profiles and user data across boots while using non-persistent virtual
desktops
Also Dell recommends to use a high performance file service to provide the profile and folder redirection
A separate array may be used to host these volumes for best performance
712 Boot and login storm considerations Section 62 demonstrated the Fluid Cache for SAN performance under boot storm To avoid any potential
IO bursts because of boot storm and degraded user experience and performances Dell recommends that
all or portion of desktops be prebooted Connection brokers such as VMware Horizon View provide the
functionality to configure number of standby desktops
713 Windows 7 master image for desktop VMs Dell recommends that the operating system be customized in order to provide the best performance in a
VDI environment This includes disabling some services which may not be required This can improve
performance for the end user VMware has a specific set of recommendations and settings for Windows 7
and Windows 8 that allow for faster logins quicker screen refreshes and generally better performance
The VMware recommendations for Windows 7 and Windows 8 image optimization can be found here
httpwwwvmwarecomresourcestechresources10157
714 VDI Management infrastructure recommendations Dell recommends to have redundancy and load balancing for all VDI management services in the case of
VMware Horizon View solution as tested here the vSphere Server VMware Horizon View Servers and SQL
Servers Ideally these should be running on clustered hosts with VMware vSphere DRS (distributed
resource scheduler) and HA (high availability) enabled
72 Server host The vSphere servers hosting the infrastructure service providers and the virtual desktops are
recommended to be configured as follows
35 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Follow VMware and Dell best practices for installing and configuring vSphere
Separate virtual switches to segregate iSCSI SAN traffic VDI traffic vMotion traffic and Management
network traffic
Each network path must be assigned to a minimum of two physical NICs for high availability
VMware Knowledge Base article about best practices for installing vSphere 55
httpkbvmwarecomkb2052329
73 Network layer Dell recommends that at least two physical NICs on each vSphere server be dedicated to the VDI network
Use VLANs to segregate different types of network traffic on the same physical network In this case Dell
recommends to separate the infrastructure vMotion and VDI LAN traffic in to separate VLANs
Do not use VLANs to segregate iSCSI SAN and Fluide Cache traffic It is required that SAN and Cache traffic
be on separate dedicated physical network to provide the best performance
Virtual switches in vSphere have a default limit of 120 ports If the number of virtual desktops on each host
exceeds the available ports vSwitch properties should be changed to support the required number of
virtual desktops This change requires a restart of the host vSphere server
On iSCSI SAN switches Spanning tree must be disabled on switch ports connected to end devices for
server and storage ports The PortFast setting must be enabled in the switch configuration for these ports
Jumbo frames and Flow control (if the NICs support it) should be enabled for all components of the iSCSI
network
More information about configuring Dell Networking switches for use with Dell Storage iSCSI SANs is
available here
httpencommunitydellcomtechcenterstoragewwiki4250switch-configuration-guides-by-sisaspx
74 Storage The Dell SC storage arrays combined with Fluid Cache is an excellent platform for providing cost-effective
performance in VDI environments
Fluid Cache for SAN extends the power of Compellent intelligent data placement from the SAN to the
server By providing a single infrastructure for data at both high- and low ends of the performance
spectrum Fluid Cache for SAN with Storage Center 65 array software eliminates the tradeoffs between
server performance and full-featured SAN benefits such as reliability manageability and data protection
Dell recommends to have separate volumes for base image and virtual desktops This enables better
manageability of the volumes easier performance monitoring and allows easy future growth
Dell recommends to use a separate high performance file service to provide file shares for roaming
profiles and user shares
36 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
8 Conclusion The technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed by using a Horizon View VDI platform leveraging Dell Fluid Cache for SAN The storage IO
characteristics under various VDI workload scenarios (boot storm login storm and steady state) along
with performance characteristics throughout the VDI stack (for example vSphere server performance and
user experience) demonstrate the optimal configuration of the infrastructure used for this VDI
deployment For more information about Fluid Cache contact your Dell account manager
37 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
A Horizon view solution configuration
Table 7 Hardware components
Hardware components Description
Virtual Desktops 4 timesDell PowerEdge R720 Servers (Fluid Cache Providers)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
2times350 GB Dell Express Flash PCIe SSDs
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
4 x Dell PowerEdge R720 Servers (Fluid Cache Clients)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55 U2 on all R720 servers Windows 7 (64 Bit) VMs
Infrastructure Servers 2 x Dell PowerEdge R720 servers
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
96 GB RAM
2times300 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55U2 on all R720 servers VMs are loaded with Microsoft Windows 2008 R2
Active Directory
VMware Horizon View 60 Server 1
VMware Horizon View 60 Server 2
VMware vCenter Server 55 update 2
VMware Horizon View Composer
SQL Server
File Server
Login VSI Launchers 8 x Dell PowerEdge M610 servers
2timesIntelreg Xeonreg E-5503 200 GHz Processors
16 GB RAM
4times146 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57711 10GbE NIC
ESXi 51 installed on all R810 servers VMs are loaded with Microsoft Windows 7 64bit Each VM supports up to 30 Login VSI launcher sessions
38 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Network Management VDI LAN
1timesDell Force10 S55 1Gb Ethernet Switch
iSCSI SAN
1timesDell Force10 S4810 10Gb Ethernet Switch
Cache network
1timesDell Force10 S4810 10Gb Ethernet Switch
One Force10 S4810 switch might suffice for all the cache iSCSI SAN VDI LAN and management traffic
Storage 2timesDell Compellent SC8000 controllers 4times6Gb SAS 4-port PCI-E Full-height cards for back-end connectivity 2times10Gb iSCSI 2 port PCI-E Low-profile IO cards for front end connectivity 1timesDell Compellent SC200 disk enclosures 12times4TB NL-SAS 6Gb 72K 35rdquo drives
User Data Infrastructure VMs Virtual Desktops
Performance Monitoring
Dell Compellent Enterprise Manager Dell Fluid Cache for SAN performance monitoring tool () vCenter Performance monitoring Liquidware Stratusphere UX
Performance monitoring on Compellent arrays Fluid Cache performance monitoring Performance monitoring and capture at the ESXi host User experience monitoring on the virtual desktop
39 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 8 Software components
Software components Description Version
Dell Fluid Cache for SAN 20
Dell Compellent Storage Center 64
Dell Compellent Enterprise Manager 64
VMware Horizon View Server 60
VMware Horizon View Composer 60
VMware Horizon View Agent 60
VMware Horizon View Client 64-bit 60
VMware ESXi Hypervisor 55 U2
VMware vCenter Server 55 U2
Microsoft SQL Server 2008R2 Enterprise x64 105016001
Client VM OS Microsoft Windows 7 Enterprise x64 SP1
Management VM OS Microsoft Windows Server 2008 Enterprise R2 x64 SP1
Microsoft Office MS office 2010 Standard Service Pack 1
Login VSI Version 40
Iometer 20060727
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
7 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
2 Dell Fluid Cache for SAN and VDI Dell Fluid Cache for SAN utilizes direct-attached Dell PowerEdge Express Flash NVMe PCIe SSDs and
remote direct memory access (RDMA) networking capabilities to create a clustered caching pool for
improved storage workload performance Applications write directly to the cache pool the
acknowledgement is sent back to the application and in the background the IO is flushed to the external
storage array Data is copied in to the cache pool when it is accessed (read) by application and is available
from the cache pool for reread operations Also data that is written into the cache pool by the application
is then available for reread operations from the application A high-speed link to other cache nodes in the
Fluid Cache for SAN pool allows the data to remain highly available by replicating blocks of data even if a
single node in cache pool stops working Fluid Cache for SAN provides a single management interface and
provides other capabilities such as cache-aware snapshots and replication and compression
Figure 1 shows an example environment highlighting how Fluid Cache for SAN communicates between
server and storage Three nodes are required to run Dell Fluid Cache for SAN software Two of these three
nodes are required to have a minimum of one Dell PowerEdge Express Flash NVMe PCIe SSD each and
the network for private cache network is based on the low-latency RDMA protocol The RDMA network
handles the cache pool communication between the nodes Creation and management of the Fluid
Cache cluster are accomplished by using the Dell Compellent Enterprise Manager software through
automatic cache server discovery
Figure 1 Dell Fluid Cache for SAN communication
8 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Fluid Cache for SAN is an ideal solution for high IOPS type VDI environment with highly write-intensive
workloads because it provides extremely fast and low-latency server-side write back caching Because
writes are mirrored across high-speed network and later destaged to the SAN with significant write
coalescing this solution can sustain significantly higher IOPSVM than an external hybrid or all-flash array
ndashbased solution could
9 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
3 Solution architecture The overall architecture of the VDI solution for the high IOPS environment is shown in the figure here
Figure 2 VDI solution architecture
31 Software Horizon view Horizon View is a VDI solution that includes a complete suite of tools for delivering desktops as a secure
and managed service from a centralized infrastructure A Horizon View infrastructure consists of many
different software network and hardware layer components This section presents an overview of the key
Horizon View components and technologies that are critical for successful design and deployment of the
VDI environment
10 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
311 Horizon view components A functional list of Horizon View components used in this solution is given in the table here
Table 1 Horizon View components
Component Description
Client Devices Personal computing devices used by end users to run the Horizon View Client These can include special end-point devices such as Dell Wyse end points mobile phones and PCs
Horizon View Connection Server
A software service that acts as a broker for client connections by authenticating and then directing the incoming user requests to the appropriate virtual desktop physical desktop or terminal server
Horizon View Client Software that is used to access the Horizon View desktops
Horizon View Agent A service that runs on all systems used as sources for Horizon View desktops and facilitates network communication between the Horizon View clients and the Horizon View server
Horizon View Administrator
A web-based administration platform for the Horizon View infrastructure components
vCenterreg Server Central administration platform for configuring provisioning and managing VMware virtualized data centers
Horizon View Composer
A service running with Horizon View servers used to create pools of virtual desktops from a shared-base image to reduce storage capacity requirements
312 Virtual desktops Virtual desktops can be classified in to two major categories persistent and non-persistent
Persistent desktop environment All configuration and personalization on the assigned desktop is kept for
the user-between sessions When using persistent desktops an administrator usually has to provision
additional storage along with other administrative requirements such as patching and upgrading of
individual desktops
Non-persistent desktop environment Users are dynamically assigned virtual desktop VMs from a pool of
resources during login This type of virtual desktop does not retain any information between sessions At
logoff all changes are simply discarded and the virtual desktop is returned to the original state Patching
and upgrading non-persistent desktops requires only making the change to the base image and refreshing
or recomposing the virtual desktop pool Thus these desktops are much easier to manage but lack the
potential for persistent user customization
11 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
313 Horizon view desktop pools A desktop pool is a term VMware uses to describe a collection of desktops that are managed as a single
entity by the Horizon View Administrator interface Horizon View desktop pools allow administrators to
group users depending on the type of service the user requires There are two types of pools ndash Automated
and Manual
In Horizon View an Automated Pool is a collection of VMs cloned from a base template while a Manual
pool is created by the Horizon View Manager from existing desktop sources physical or virtual For each
desktop in the Manual pool the administrator selects a desktop source to deliver Horizon View access to
the clients
VMware View Personas profile management features can be used to achieve persistent desktop-like
behavior on non-persistent desktops By using these features an administrator can design a user account
where the configuration settings are written to a remote profile that is stored separately from the virtual
desktop image files This reduces the need for additional management on individual virtual desktops while
still providing a customized user experience
314 Using linked clones Significant storage space savings and increased efficiencies in desktop VM provisioning and administration
are possible when using VMware-linked clones A linked clone is a duplicate VM that shares the same base
image with the original VM but has separate differential data disks to track the differences from the
original one Each linked clone functions as an independent desktop VM with its own unique identity
Because linked clones share the same base image they consume significantly less storage disk space than
a set of completely independent VM images Temporary system data and other data unique to each linked
clone desktop VM are written to separate differential data storage and these temporary changes are
discarded during restart andor user logoff Persistent data such as user profiles applications and user
data can be optionally redirected to a CIFS share With this model software maintenance updates
antivirus remediation and patches need to be applied only on the base image These base image changes
automatically take effect on all linked clones without affecting any user settings and data
To configure linked clones the administrator creates a snapshot of a parent VM image with the required
OS settings and software installed Horizon View Composer first creates a full replica (clone) of the parent
VM and then uses this replica to create linked clones The replica can be placed on the same data store as
the linked clones or on a separate data store
More information about configuring linked clones can be found in the ldquoCreating Desktop Poolsrdquo section of
the VMware Horizon View Online Library here
315 Hypervisor platform VMware vSphere 55 VMware vSphere 55 is the enterprise virtualization platform used for building VDI and cloud
infrastructures VMware vSphere 55 includes three major layers virtualization management and interface
The virtualization layer includes infrastructure and application services The management layer is central
12 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
for configuring provisioning and managing virtualized environments The interface layer includes the
vSphere client and the vSphere web client
Throughout the solution all VMware and Microsoft best practices and prerequisites for core services were
used (NTP DNS Active Directory and others)
32 Hardware Dell infrastructure Figure 3 shows the design of the infrastructure for the Horizon Viewndashbased high IOPS type VDI
deployment that leverages Fluid Cache
An eight-node vSphere server cluster is used to host the virtual desktops Each of these server nodes has a
direct-attached PCIe SSD that is added to the Fluid Cache pool thus making each server a Fluid Cache
Provider (a server contributing to the Fluid Cache capacity) The eight PCIe SSDs were distributed among
all the servers to better balance the load on the Fluid Cache server Fluid Cache server1 These servers
were connected by using a private caching network to provide the Fluid Cache functionality Also the
servers were connected through a separate managementVDI client network and a 10 GB Ethernet iSCSI
SAN network
Another two-node vSphere server cluster is used to host the VDI infrastructure VMs such as vCenter
server View Connection server View Composer server SQL Server and Active Directory etc These
infrastructure servers were connected to the management network and the iSCSI SAN network
The Compellent storage array for the solution has two controllers and a mix of Write Intensive (WI) SSDs
15K SAS HDDs and 72K NL-SAS HDDs to provide the optimal performance and capacity needed for the
solution
Two switches are stacked together for different networks to provide redundancy in the networking layer
Ideally 40 GB Ethernet switches are recommended for the cache network While 1 GB Ethernet switches
can be used for management network it is better to use 10 GB Ethernet switches combining management
and VDI client networks The same 10 GB Ethernet switches can be used for iSCSI SAN also (with different
network traffic segmented by VLANs) provided they have adequate bandwidth needed for the specific VDI
deployment
Information about how this reference architecture was developed ensuring the optimal utilization across
the servers switches and storage arrays is discussed later in the following sections of this technical white
paper
1 Fluid Cache does not require all servers to be a Fluid Cache Provider For example in this case four
servers could have two PCIe SSDs each This configuration with four Fluid Cache Provider and four Fluid Cache Client would have had same capacity for Fluid Cache pool and all eight servers could have taken advantage of Fluid Cache However the chosen configuration for the technical white paper provides better performance the because VDI application caching load is unforming distributed among all the available servers
13 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 3 Infrastructure Set-up for VDI Solution
1 Enterprise Manager Console 2 Management and VDI Client Network 3 vSphere Servers hosting virtual desktops 4 Cache network switches (2)
5 SAN switch 6 Storage Center controllers (2) 7 Storage Center expansion enclosures (2) 8 Server hosting VDI infrastructure VMs
(Server 1) (Server 2)
14 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
4 Solution configuration This section provides information about the solution configuration and test setup for hosting Horizon View
virtual desktops including infrastructure components networking and storage subsystems
41 Host design considerations The entire VDI solution was installed in two vSphere server clusters The clusters included
Figure 4 vSphere server clusters
Infrastructure Cluster Two Dell PowerEdge R720 servers hosting VMs for Active Directory
services VMware vCenter 55 server Horizon View Connection server (primary and secondary)
View Composer server Microsoft Windows Server 2012 R2 based file server and SQL Server 2012
R2
View Client Cluster Eight Dell PowerEdge R720 servers hosting the virtual desktops Each server
had
o 2times10 core Intel Xeon CPU E5-2690v2 300GHz
o 256 GB RAM
o 1times350 GB Dell Express Flash PCIe SSD
o 1timesMellanox Connect ndash X3 card
o 1timesDual-port Broadcom NetXtreme II BCM57810 10 Gigabit NIC
o 1timesQuad-port Broadcom NetXtreme BCM5720 Gigabit NIC
Along with the other servers the above servers 40 LoginVSI launcher VMs were used to generate VDI
workload They can be hosted by two PowerEdge R720 servers or equivalent for VDI load generation
purposes
15 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
42 Network design considerations Figure 5 here shows the network layout of one of the eight PowerEdge R720 servers with vSphere 55
installed
Figure 5 vSphere host network configuration
Three network switches are used in the Fluid Cache for VDI implementation One Force10 S55 1 GB switch
for all management traffic and VDI traffic The management traffic includes hosts and vSphere
management Compellent storage management and so on The networks are segregated by using VLANs
to separate different types of traffic
One Dell Force10 S4810 10 GB switch is used for Fluid Cache cache network which supports all the traffic
between cache layer on eight VDI VM hosts Another Force10 S4810 10 GB switch is used for iSCSI
network between infrastructure hosts VDI VM hosts and Compellent SC8000
Appendix B has extended information on the vSwitch configuration for each vSphere host
16 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
43 Dell Compellent SC8000 storage array configurations The storage used to host the virtual desktops was a Dell Compellent SC8000 array running Storage Center
Operating System (SCOS) 65 All two front-end ports were 10 GB iSCSI and all two back-end ports were
six GB serial-attached SCSI (SAS) The array used two external enclosures with Write Intensive (WI) SSDs
comprising Tier 1 and 15K SAS HDDs comprising Tier 2 for performance Also 72 NL-SAS drives were
used in Tier 3 to provide capacity for user data Table 2 summarizes the storage hardware configuration
Table 2 Storage hardware components
Storage role Type Qty Description
Controllers SC8000 2 System Center Operating System (SCOS) 65
Enclosures External 2 24 bay ndash 25rdquo disk drive enclosure
Ports Ethernet ndash 10 Gbps 2 Front end host connectivity
SAS - 6 Gbps 4 Back end drive connectivity
Drives 400 GB WI SSD 12 11 active with 1 hot spare
300 GB 15K SAS HDD
21 20 active with 1 hot spare
4 TB 72K NL-SAS HDD
12 11 active with 1 hot spare
The volumes created to host the virtual desktops took advantage of the Compellent Dynamic Capacity
technology for efficient capacity allocation Table 3 lists the volume layout used for the infrastructure
functions including user data
Table 3 Volume layout for hosting infrastructure components and user data
Volume name Size Purpose
Infrastructure 500 GB Storage for Active Directory SQL Server vCenter Server View Connection Server View Composer and File Server
UserSpace 2 TB Storage for User profiles and folder redirection space (Average 25 GB per user)
Along with the infrastructure volumes the storage array also provided shared storage for hosting the
virtual desktops The volume layout used for configuring the base image (View Composer Replica) and VDI
volumes on the array is shown in Table 4
17 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 4 Dell Storage PS4210XS layout for volumes hosting virtual desktops
Volume name Size Purpose
View-Replicas1 and 2 100 GB each Storage for base image for VDI deployment
VDI-Images1 through 8 500 GB each Storage for VDI VMs in VDI Cluster Each volume hosted 100 desktops
44 vSphere host network configuration VMware vSphere 55 hypervisor was installed on all servers The network configuration on each of those
hosts is described here Each vSphere host was configured with five virtual switches vSwitch0 vSwitch1
vSwitch2 vSwitch3 and vSwitch4 to separate different types of traffic on the system
Table 5 vSwitch configuration in vSphere hosts
vSwitch Description
vSwitch0 Management Network
vSwitch1 and vSwitch2 iSCSI SAN
vSwitch3 Fluid Cache VLAN
vSwitch4 VDI LAN
For additional information about individual vSwitch configuration refer to Appendix B in the Dell technical
white paper
45 Horizon view configuration Horizon View 60 was installed by using the documentation provided by VMware
Horizon View 601 installation documentation
httpswwwvmwarecomsupportpubsview_pubshtml
Table 6 Specific configuration used in the tests
Purpose Count Type Memory CPU
Horizon View Connection Servers
2 VM 16 GB 8nos
View Composer Server 1 VM 8 GB 8nos
18 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
46 Windows 7 VM configuration Following the guidelines from VMware and Login VSI the Windows 7 base image was generated based on
a generic base VM with the following properties
VMware Virtual Hardware version 8
Two virtual CPU
3 GB RAM with 15GB reserved
25 GB virtual hard drive
One virtual NIC connected to the VDI network
Windows 7 64-bit OS
Also the base image was customized by using the VMware Horizon with View Optimization Guide for
Windows 7 and Windows 8 available at this location httpwwwvmwarecomfilespdfVMware-View-
OptimizationGuideWindows7-ENpdf
19 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
5 Horizon view test methodology This section outlines the test objectives along with the test tools and criteria used to determine the
optimal virtual desktop density and best practices for deploying Horizon View on Dell Fluid Cache for SAN
for high IOPS type VDI environment
51 Test objectives As noted in Section 11 the test objectives were
Develop an optimal end-to-end infrastructure design for a Horizon View and vSpherendashbased high
user type of VDI solution deployed by using the Fluid Cache Compellent storage PowerEdge
servers and Dell Networking switches
Determine the performance at every layer of the VDI solution stack under high IOPS workload For
example desktops generating 80ndash90 IOPSVM at steady state
Determine the performance impact of peak IO activity such as boot and login storms
52 Test tools All tests were conducted by using Login VSI 40 as the workload generator and user experience analyzer
tool Login VSI is a benchmarking tool to measure the performance and scalability of centralized desktop
environments such as Server Based Computing (SBC) and VDI
Note More information can be found at the Login VSI website httpwwwloginvsicom
In addition to Login VSI Iometer is used in desktop VMs to simulate high IOPS conditions Iometer is
invoked in desktop VMs by using custom scripting of Login VSI workloads
Note More information can be found at the Iometer project website httpwwwiometerorg
521 Load generation First the ldquoMediumrdquo workload from Login VSI was used to simulate the standard user workload The
characteristics of the Medium workload are
Up to five applications are started simultaneously
Applications include Microsoft Internet Explorer Microsoft Word Microsoft Excel Microsoft
PowerPoint PDF reader 7-Zip compression software Movie player and FreeMind
After a session is started the medium workload repeats approximately after every 48 minutes
During a loop the response time is measured after every 3ndash4 minutes
Idle time is about two minutes in each 48-minute loop
Type rate is approximately 160 milliseconds per character
After the test by using Login VSI Medium was complete tests were rerun with Login VSI Medium and
Iometer in desktop VMs to simulate high IOPS VDI workload While the Login VSI Medium generates 8ndash10
20 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
IOPSVM the latter method was able to generate 80ndash90 IOPSVM For these tests each VM in the Horizon
view pool is created with standard LoginVSI contents and applications Also Iometer is installed on each
VM After the user logs in a customized logon script starts the Iometer with required IO specification (icf
file)
522 Monitoring tools The following monitoring tools were used
Dell Compellent Enterprise Manager for monitoring Fluid Cache and Compellent SC8000 storage
array performance
VMware vCenter statistics for vSphere performance
Login VSI Analyzer for end user performance statistics
Detailed performance metrics were captured from the storage arrays hypervisors virtual desktops and
the load generators during the tests
53 Test criteria The primary focus of the tests is to validate the 800 desktop high IOPS type of VDI architecture with
acceptable user experience by using Fluid Cache for SAN VDI configurations involve many components at
different layers ndash application hypervisor server network and storage As a result multiple metrics need to
be captured at different layers to ensure that the environment is healthy and performing optimally and
appropriately for all users
The specific test criteria are described in the following sections
531 Storage capacity and IO latency The typical industry standard latency limit for storage disk IO is 10 milliseconds Maintaining this limit
ensures good user application response times when there are no other bottlenecks at the infrastructure
layer In addition Dell recommends to maintain a 10 percent spare disk space on the storage array for
optimal performance
532 System utilization at the hypervisor Even though the primary focus of these tests was storage characterization additional metrics at the
hypervisor infrastructure layer were defined to ensure solution consistency These were
CPU utilization on any vSphere server must not exceed 85 percent
Minimal memory ballooning on the VMs
Total network bandwidth utilization must not exceed 90 percent on any one link
TCPIP storage network retransmissions should be less than 05 percent
21 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
533 Virtual desktop user experience Login VSI Analyzer was also used to gather metrics on the user experience at the virtual desktop layer to
ensure that all the desktops had acceptable levels of application performance Login VSI uses the VSImax
parameter to determine the maximum number of sessions that can be obtained from a deployed solution
The calculation methodology used in VSImax is available here
httpwwwloginvsicomdocumentationindexphptitle=Analyzing_Results
534 Test configuration A single virtual desktop pool was configured by using the VMware Horizon View Administrator interface
Each pool was built from a Windows 7 base image The Windows 7 configuration information is available
in Section 46
Desktop pool properties
Automatic Desktop Pool
Users are assigned using Floating assignments
View Storage Accelerator is enabled for all hosts with a refresh period of seven days
800 desktops were deployed across eight hosts (100 desktops a host)
Replica images were stored on a separate volume
22 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
6 Test results and analysis This section presents the results from the different Horizon View VDI characterization tests and the key
findings from each test The testing was focused on the high IOPS workload profile
61 Test scenarios The following tests were conducted to gather results and analysis on the solution stack
1 Boot storm Boot storms represent the worst-case scenario where many virtual desktops are
turned on at the same time and they all contend for the system resources simultaneously This test
was used to evaluate if the storage array hosting the desktops was capable of handling huge
variation in storage IO without causing significant impact on other services
2 Login storm Login storms also represent a high IOPS situation where many users are logging in to
their virtual desktops at the beginning of a workday or a shift In this test all the desktops were
pre-booted and left in an idle state for more than 20 minutes to let their IO settle before running
the Login VSI Medium workload to simulate users logging in to their virtual desktops
3 Steady state workload for standard users with normal IOPS After the login storm for the previous
test was completed the Login VSI Medium workload was allowed to run for at least one hour to
simulate the real-world scenario of users performing their daily tasks The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
4 Steady state workload for users with high IOPS The previous test was repeated with the Login
VSI Medium workload and Iometer scripts in desktop VMs as described in Section 521 to simulate
real-world heavy users performing their daily tasks with high IOPS The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
The following sections provide results from the boot storm login storm and steady state testing for the
Fluid Cache for SAN based VDI solution
23 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
62 Boot storm IO To simulate a boot storm the virtual desktops were reset simultaneously from the VMware vSphere client
Figure 6 shows the IO pattern on the Fluid Cache for the boot storm
Figure 6 SAN HQ data showing boot storm performance with Fluid Cache array
With 800 desktops the boot storm generated about 115000 total IOPS with a majority of them being
write operations All desktops were available for use in less than four minutes
24 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
63 Login storm and steady state for standard users (LoginVSI
Medium) Login VSI was programmed to start 800 virtual desktops over a period of about 60 minutes after pre-
booting the virtual desktops The peak IOPS during the login storm observed by the vSphere servers
hosting the desktops was about 6500 IOPS (8ndash10 IOPS a VM)
In a standard user environment login storms generate significantly more write IOPS than a boot storm or
steady state because of multiple factors such as
User profile activity
Starting operating system services on the desktop
First start of applications
After a virtual desktop has achieved a steady state after user login the Windows 7 OS has cached
applications in memory and does not need to access storage each time the application is started This
leads to lesser IOPS during the steady state Figure 7 here shows the various IO characteristics during the
login storm and steady state of these tests
25 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 7 IOPS and Cache Hit for the standard user test
On the Fluid Cache layer the maximum IOPS reached 6500 with cache-hit reaching 100 percent and
read-hit around 95 percent As shown in the Figure 8 here the throughput peaked at 98 MBps with a low
latency of less than 2 msec
26 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 8 Throughput and Latency for the standard user test
631 Server host performance During the login storm and steady state of the test the vSphere host CPU memory network and storage
performance were measured on all the servers that hosted the virtual desktops The performance of one
such vSphere server is given here The other vSphere servers had similar performance characteristics
Statistics for the vSphere hosts were captured by using VMware vCenter Server The figures here show the
CPU memory and network utilization for boot storm login storm and steady state of one of the vSphere
servers hosting the virtual desktops The results shown here are for a test run with 800 no standard user
desktops in the desktop pool
27 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 9 Average CPU performance per core on one vSphere host during login storm and steady state
Figure 10 Disk space usage during login storm and steady state
0
10
20
30
40
50
60
70
80
90
100
1020 1045 1110 1135 1200 1225
Per
cen
t
Time
CPU Performance
0
50
100
150
200
250
300
1020 1040 1100 1120 1140 1200 1220
GB
Time
Memory Performance
Granted Swap used Shared common
28 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 11 Overall network performance during login storm and steady state
Figure 12 Storage adapter performance during login storm and steady state
0
10000
20000
30000
40000
50000
60000
70000
1020 1045 1110 1135 1200 1225
kBp
s
Time
Network Performance
0
05
1
15
2
25
1020 1045 1110 1135 1200 1225
mSe
c
Time
Storage adaptor performance
29 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
The key observations from the statistics were
CPU utilization was less than the 85 percent threshold throughout the test
Active disk space usage was about 80 percent during the boost storm and about 60 percent
during login storm and steady state There was minimal-or no memory ballooning observed
Network utilization was about 45 percent which included all the networks such as iSCSI SAN VDI
LAN Management LAN and vMotion LAN
Average read- and write latencies at the storage adapter level were very close to the observed
latencies in Fluid Cache 2 msec
632 Monitoring user experience Figure 13 here shows the response time as experienced by each user as calculated by Login VSI The graph
clearly shows that the VSImax (Dynamic) value has not been reached and there were non-responsive or
inactive sessions This means that the array is capable of supporting the 1000 desktops and all users have
acceptable response times for applications that the user is has started
Figure 13 Login VSI user experience monitoring for 800 standard user desktops
30 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
633 Standard user test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SANndashbased VDI solution is able to host 800 virtual desktops and support
a standard user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only operations and
less than 2 percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to handle this login storm easily with low latency mdash it delivered the required 6500 IOPS with less
than 2 milliseconds of write latency with a 99 percent write VDI IO workload
64 Login storm and steady state with high IOPS (LoginVSI Medium +
Iometer) As mentioned earlier Iometer was used in desktop VMs alongside the Login VSI Medium workload to
simulate high IOPS type of VDI environment To mimic actual VDI workload profile the following Iometer
profile was used
20 KB block size 80 percent write 75 percent random with 25 msec burst delay
Figure 14 here shows the various IO characteristics during the login storm and steady state of these tests
Figure 14 IOPS and Cache Hit for the high IOPS test
On the Fluid Cache layer the maximum IOPS reached was approximately 72000 (or 90 IOPSVM) with
cache write-hit 100 percent and read-hit around 95 percent As shown in the Figure 15 the throughput
peaked at greater than 900 MBps with a peak latency of approximately 75 msec
31 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 15 Throughput and Latency for the high IOPS test
32 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
641 Server host performance Similar to the standard user test statistics for the vSphere hosts were captured by using VMware vCenter
Server during the high IOPS (heavy user) test also There are no significant differences in CPU disk space
and network utilization between standard users and heavy users The storage adapter latency is also
showing similar on hosts and observed on Fluid Cache
642 User experience monitoring Figure 16 here shows the response time as experienced by each user as calculated by Login VSI for the
heavy user test The graph shows that the VSImax (Dynamic) value was 796 indicating that the solution is
capable of supporting the 800 user high IOPS desktops with 90 IOPSVM
Figure 16 Login VSI user experience monitoring for 800 user high IOPS desktops
33 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
643 High IOPS (heavy user) test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SAN based VDI solution is able to host 800 virtual desktops and support a
high user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only and less than 2
percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to easily handle this login storm with low latency Subsequently it was able to handle 72000 IOPS
at high IOPS steady state with 90 IOPSVM with a maximum of 75 msec latency
34 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
7 Best practices This section provides the best practices derived from the testing and analysis in Section 6
71 Virtual Desktop Infrastructure This section provides best practices for the implementation of VDI using Dell Fluid Cache for SAN
711 Implement roaming profiles and folder redirection Dell recommends that all users in the VDI environment be configured with roaming profiles and folder
redirection This preserves user profiles and user data across boots while using non-persistent virtual
desktops
Also Dell recommends to use a high performance file service to provide the profile and folder redirection
A separate array may be used to host these volumes for best performance
712 Boot and login storm considerations Section 62 demonstrated the Fluid Cache for SAN performance under boot storm To avoid any potential
IO bursts because of boot storm and degraded user experience and performances Dell recommends that
all or portion of desktops be prebooted Connection brokers such as VMware Horizon View provide the
functionality to configure number of standby desktops
713 Windows 7 master image for desktop VMs Dell recommends that the operating system be customized in order to provide the best performance in a
VDI environment This includes disabling some services which may not be required This can improve
performance for the end user VMware has a specific set of recommendations and settings for Windows 7
and Windows 8 that allow for faster logins quicker screen refreshes and generally better performance
The VMware recommendations for Windows 7 and Windows 8 image optimization can be found here
httpwwwvmwarecomresourcestechresources10157
714 VDI Management infrastructure recommendations Dell recommends to have redundancy and load balancing for all VDI management services in the case of
VMware Horizon View solution as tested here the vSphere Server VMware Horizon View Servers and SQL
Servers Ideally these should be running on clustered hosts with VMware vSphere DRS (distributed
resource scheduler) and HA (high availability) enabled
72 Server host The vSphere servers hosting the infrastructure service providers and the virtual desktops are
recommended to be configured as follows
35 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Follow VMware and Dell best practices for installing and configuring vSphere
Separate virtual switches to segregate iSCSI SAN traffic VDI traffic vMotion traffic and Management
network traffic
Each network path must be assigned to a minimum of two physical NICs for high availability
VMware Knowledge Base article about best practices for installing vSphere 55
httpkbvmwarecomkb2052329
73 Network layer Dell recommends that at least two physical NICs on each vSphere server be dedicated to the VDI network
Use VLANs to segregate different types of network traffic on the same physical network In this case Dell
recommends to separate the infrastructure vMotion and VDI LAN traffic in to separate VLANs
Do not use VLANs to segregate iSCSI SAN and Fluide Cache traffic It is required that SAN and Cache traffic
be on separate dedicated physical network to provide the best performance
Virtual switches in vSphere have a default limit of 120 ports If the number of virtual desktops on each host
exceeds the available ports vSwitch properties should be changed to support the required number of
virtual desktops This change requires a restart of the host vSphere server
On iSCSI SAN switches Spanning tree must be disabled on switch ports connected to end devices for
server and storage ports The PortFast setting must be enabled in the switch configuration for these ports
Jumbo frames and Flow control (if the NICs support it) should be enabled for all components of the iSCSI
network
More information about configuring Dell Networking switches for use with Dell Storage iSCSI SANs is
available here
httpencommunitydellcomtechcenterstoragewwiki4250switch-configuration-guides-by-sisaspx
74 Storage The Dell SC storage arrays combined with Fluid Cache is an excellent platform for providing cost-effective
performance in VDI environments
Fluid Cache for SAN extends the power of Compellent intelligent data placement from the SAN to the
server By providing a single infrastructure for data at both high- and low ends of the performance
spectrum Fluid Cache for SAN with Storage Center 65 array software eliminates the tradeoffs between
server performance and full-featured SAN benefits such as reliability manageability and data protection
Dell recommends to have separate volumes for base image and virtual desktops This enables better
manageability of the volumes easier performance monitoring and allows easy future growth
Dell recommends to use a separate high performance file service to provide file shares for roaming
profiles and user shares
36 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
8 Conclusion The technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed by using a Horizon View VDI platform leveraging Dell Fluid Cache for SAN The storage IO
characteristics under various VDI workload scenarios (boot storm login storm and steady state) along
with performance characteristics throughout the VDI stack (for example vSphere server performance and
user experience) demonstrate the optimal configuration of the infrastructure used for this VDI
deployment For more information about Fluid Cache contact your Dell account manager
37 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
A Horizon view solution configuration
Table 7 Hardware components
Hardware components Description
Virtual Desktops 4 timesDell PowerEdge R720 Servers (Fluid Cache Providers)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
2times350 GB Dell Express Flash PCIe SSDs
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
4 x Dell PowerEdge R720 Servers (Fluid Cache Clients)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55 U2 on all R720 servers Windows 7 (64 Bit) VMs
Infrastructure Servers 2 x Dell PowerEdge R720 servers
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
96 GB RAM
2times300 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55U2 on all R720 servers VMs are loaded with Microsoft Windows 2008 R2
Active Directory
VMware Horizon View 60 Server 1
VMware Horizon View 60 Server 2
VMware vCenter Server 55 update 2
VMware Horizon View Composer
SQL Server
File Server
Login VSI Launchers 8 x Dell PowerEdge M610 servers
2timesIntelreg Xeonreg E-5503 200 GHz Processors
16 GB RAM
4times146 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57711 10GbE NIC
ESXi 51 installed on all R810 servers VMs are loaded with Microsoft Windows 7 64bit Each VM supports up to 30 Login VSI launcher sessions
38 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Network Management VDI LAN
1timesDell Force10 S55 1Gb Ethernet Switch
iSCSI SAN
1timesDell Force10 S4810 10Gb Ethernet Switch
Cache network
1timesDell Force10 S4810 10Gb Ethernet Switch
One Force10 S4810 switch might suffice for all the cache iSCSI SAN VDI LAN and management traffic
Storage 2timesDell Compellent SC8000 controllers 4times6Gb SAS 4-port PCI-E Full-height cards for back-end connectivity 2times10Gb iSCSI 2 port PCI-E Low-profile IO cards for front end connectivity 1timesDell Compellent SC200 disk enclosures 12times4TB NL-SAS 6Gb 72K 35rdquo drives
User Data Infrastructure VMs Virtual Desktops
Performance Monitoring
Dell Compellent Enterprise Manager Dell Fluid Cache for SAN performance monitoring tool () vCenter Performance monitoring Liquidware Stratusphere UX
Performance monitoring on Compellent arrays Fluid Cache performance monitoring Performance monitoring and capture at the ESXi host User experience monitoring on the virtual desktop
39 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 8 Software components
Software components Description Version
Dell Fluid Cache for SAN 20
Dell Compellent Storage Center 64
Dell Compellent Enterprise Manager 64
VMware Horizon View Server 60
VMware Horizon View Composer 60
VMware Horizon View Agent 60
VMware Horizon View Client 64-bit 60
VMware ESXi Hypervisor 55 U2
VMware vCenter Server 55 U2
Microsoft SQL Server 2008R2 Enterprise x64 105016001
Client VM OS Microsoft Windows 7 Enterprise x64 SP1
Management VM OS Microsoft Windows Server 2008 Enterprise R2 x64 SP1
Microsoft Office MS office 2010 Standard Service Pack 1
Login VSI Version 40
Iometer 20060727
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
8 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Fluid Cache for SAN is an ideal solution for high IOPS type VDI environment with highly write-intensive
workloads because it provides extremely fast and low-latency server-side write back caching Because
writes are mirrored across high-speed network and later destaged to the SAN with significant write
coalescing this solution can sustain significantly higher IOPSVM than an external hybrid or all-flash array
ndashbased solution could
9 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
3 Solution architecture The overall architecture of the VDI solution for the high IOPS environment is shown in the figure here
Figure 2 VDI solution architecture
31 Software Horizon view Horizon View is a VDI solution that includes a complete suite of tools for delivering desktops as a secure
and managed service from a centralized infrastructure A Horizon View infrastructure consists of many
different software network and hardware layer components This section presents an overview of the key
Horizon View components and technologies that are critical for successful design and deployment of the
VDI environment
10 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
311 Horizon view components A functional list of Horizon View components used in this solution is given in the table here
Table 1 Horizon View components
Component Description
Client Devices Personal computing devices used by end users to run the Horizon View Client These can include special end-point devices such as Dell Wyse end points mobile phones and PCs
Horizon View Connection Server
A software service that acts as a broker for client connections by authenticating and then directing the incoming user requests to the appropriate virtual desktop physical desktop or terminal server
Horizon View Client Software that is used to access the Horizon View desktops
Horizon View Agent A service that runs on all systems used as sources for Horizon View desktops and facilitates network communication between the Horizon View clients and the Horizon View server
Horizon View Administrator
A web-based administration platform for the Horizon View infrastructure components
vCenterreg Server Central administration platform for configuring provisioning and managing VMware virtualized data centers
Horizon View Composer
A service running with Horizon View servers used to create pools of virtual desktops from a shared-base image to reduce storage capacity requirements
312 Virtual desktops Virtual desktops can be classified in to two major categories persistent and non-persistent
Persistent desktop environment All configuration and personalization on the assigned desktop is kept for
the user-between sessions When using persistent desktops an administrator usually has to provision
additional storage along with other administrative requirements such as patching and upgrading of
individual desktops
Non-persistent desktop environment Users are dynamically assigned virtual desktop VMs from a pool of
resources during login This type of virtual desktop does not retain any information between sessions At
logoff all changes are simply discarded and the virtual desktop is returned to the original state Patching
and upgrading non-persistent desktops requires only making the change to the base image and refreshing
or recomposing the virtual desktop pool Thus these desktops are much easier to manage but lack the
potential for persistent user customization
11 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
313 Horizon view desktop pools A desktop pool is a term VMware uses to describe a collection of desktops that are managed as a single
entity by the Horizon View Administrator interface Horizon View desktop pools allow administrators to
group users depending on the type of service the user requires There are two types of pools ndash Automated
and Manual
In Horizon View an Automated Pool is a collection of VMs cloned from a base template while a Manual
pool is created by the Horizon View Manager from existing desktop sources physical or virtual For each
desktop in the Manual pool the administrator selects a desktop source to deliver Horizon View access to
the clients
VMware View Personas profile management features can be used to achieve persistent desktop-like
behavior on non-persistent desktops By using these features an administrator can design a user account
where the configuration settings are written to a remote profile that is stored separately from the virtual
desktop image files This reduces the need for additional management on individual virtual desktops while
still providing a customized user experience
314 Using linked clones Significant storage space savings and increased efficiencies in desktop VM provisioning and administration
are possible when using VMware-linked clones A linked clone is a duplicate VM that shares the same base
image with the original VM but has separate differential data disks to track the differences from the
original one Each linked clone functions as an independent desktop VM with its own unique identity
Because linked clones share the same base image they consume significantly less storage disk space than
a set of completely independent VM images Temporary system data and other data unique to each linked
clone desktop VM are written to separate differential data storage and these temporary changes are
discarded during restart andor user logoff Persistent data such as user profiles applications and user
data can be optionally redirected to a CIFS share With this model software maintenance updates
antivirus remediation and patches need to be applied only on the base image These base image changes
automatically take effect on all linked clones without affecting any user settings and data
To configure linked clones the administrator creates a snapshot of a parent VM image with the required
OS settings and software installed Horizon View Composer first creates a full replica (clone) of the parent
VM and then uses this replica to create linked clones The replica can be placed on the same data store as
the linked clones or on a separate data store
More information about configuring linked clones can be found in the ldquoCreating Desktop Poolsrdquo section of
the VMware Horizon View Online Library here
315 Hypervisor platform VMware vSphere 55 VMware vSphere 55 is the enterprise virtualization platform used for building VDI and cloud
infrastructures VMware vSphere 55 includes three major layers virtualization management and interface
The virtualization layer includes infrastructure and application services The management layer is central
12 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
for configuring provisioning and managing virtualized environments The interface layer includes the
vSphere client and the vSphere web client
Throughout the solution all VMware and Microsoft best practices and prerequisites for core services were
used (NTP DNS Active Directory and others)
32 Hardware Dell infrastructure Figure 3 shows the design of the infrastructure for the Horizon Viewndashbased high IOPS type VDI
deployment that leverages Fluid Cache
An eight-node vSphere server cluster is used to host the virtual desktops Each of these server nodes has a
direct-attached PCIe SSD that is added to the Fluid Cache pool thus making each server a Fluid Cache
Provider (a server contributing to the Fluid Cache capacity) The eight PCIe SSDs were distributed among
all the servers to better balance the load on the Fluid Cache server Fluid Cache server1 These servers
were connected by using a private caching network to provide the Fluid Cache functionality Also the
servers were connected through a separate managementVDI client network and a 10 GB Ethernet iSCSI
SAN network
Another two-node vSphere server cluster is used to host the VDI infrastructure VMs such as vCenter
server View Connection server View Composer server SQL Server and Active Directory etc These
infrastructure servers were connected to the management network and the iSCSI SAN network
The Compellent storage array for the solution has two controllers and a mix of Write Intensive (WI) SSDs
15K SAS HDDs and 72K NL-SAS HDDs to provide the optimal performance and capacity needed for the
solution
Two switches are stacked together for different networks to provide redundancy in the networking layer
Ideally 40 GB Ethernet switches are recommended for the cache network While 1 GB Ethernet switches
can be used for management network it is better to use 10 GB Ethernet switches combining management
and VDI client networks The same 10 GB Ethernet switches can be used for iSCSI SAN also (with different
network traffic segmented by VLANs) provided they have adequate bandwidth needed for the specific VDI
deployment
Information about how this reference architecture was developed ensuring the optimal utilization across
the servers switches and storage arrays is discussed later in the following sections of this technical white
paper
1 Fluid Cache does not require all servers to be a Fluid Cache Provider For example in this case four
servers could have two PCIe SSDs each This configuration with four Fluid Cache Provider and four Fluid Cache Client would have had same capacity for Fluid Cache pool and all eight servers could have taken advantage of Fluid Cache However the chosen configuration for the technical white paper provides better performance the because VDI application caching load is unforming distributed among all the available servers
13 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 3 Infrastructure Set-up for VDI Solution
1 Enterprise Manager Console 2 Management and VDI Client Network 3 vSphere Servers hosting virtual desktops 4 Cache network switches (2)
5 SAN switch 6 Storage Center controllers (2) 7 Storage Center expansion enclosures (2) 8 Server hosting VDI infrastructure VMs
(Server 1) (Server 2)
14 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
4 Solution configuration This section provides information about the solution configuration and test setup for hosting Horizon View
virtual desktops including infrastructure components networking and storage subsystems
41 Host design considerations The entire VDI solution was installed in two vSphere server clusters The clusters included
Figure 4 vSphere server clusters
Infrastructure Cluster Two Dell PowerEdge R720 servers hosting VMs for Active Directory
services VMware vCenter 55 server Horizon View Connection server (primary and secondary)
View Composer server Microsoft Windows Server 2012 R2 based file server and SQL Server 2012
R2
View Client Cluster Eight Dell PowerEdge R720 servers hosting the virtual desktops Each server
had
o 2times10 core Intel Xeon CPU E5-2690v2 300GHz
o 256 GB RAM
o 1times350 GB Dell Express Flash PCIe SSD
o 1timesMellanox Connect ndash X3 card
o 1timesDual-port Broadcom NetXtreme II BCM57810 10 Gigabit NIC
o 1timesQuad-port Broadcom NetXtreme BCM5720 Gigabit NIC
Along with the other servers the above servers 40 LoginVSI launcher VMs were used to generate VDI
workload They can be hosted by two PowerEdge R720 servers or equivalent for VDI load generation
purposes
15 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
42 Network design considerations Figure 5 here shows the network layout of one of the eight PowerEdge R720 servers with vSphere 55
installed
Figure 5 vSphere host network configuration
Three network switches are used in the Fluid Cache for VDI implementation One Force10 S55 1 GB switch
for all management traffic and VDI traffic The management traffic includes hosts and vSphere
management Compellent storage management and so on The networks are segregated by using VLANs
to separate different types of traffic
One Dell Force10 S4810 10 GB switch is used for Fluid Cache cache network which supports all the traffic
between cache layer on eight VDI VM hosts Another Force10 S4810 10 GB switch is used for iSCSI
network between infrastructure hosts VDI VM hosts and Compellent SC8000
Appendix B has extended information on the vSwitch configuration for each vSphere host
16 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
43 Dell Compellent SC8000 storage array configurations The storage used to host the virtual desktops was a Dell Compellent SC8000 array running Storage Center
Operating System (SCOS) 65 All two front-end ports were 10 GB iSCSI and all two back-end ports were
six GB serial-attached SCSI (SAS) The array used two external enclosures with Write Intensive (WI) SSDs
comprising Tier 1 and 15K SAS HDDs comprising Tier 2 for performance Also 72 NL-SAS drives were
used in Tier 3 to provide capacity for user data Table 2 summarizes the storage hardware configuration
Table 2 Storage hardware components
Storage role Type Qty Description
Controllers SC8000 2 System Center Operating System (SCOS) 65
Enclosures External 2 24 bay ndash 25rdquo disk drive enclosure
Ports Ethernet ndash 10 Gbps 2 Front end host connectivity
SAS - 6 Gbps 4 Back end drive connectivity
Drives 400 GB WI SSD 12 11 active with 1 hot spare
300 GB 15K SAS HDD
21 20 active with 1 hot spare
4 TB 72K NL-SAS HDD
12 11 active with 1 hot spare
The volumes created to host the virtual desktops took advantage of the Compellent Dynamic Capacity
technology for efficient capacity allocation Table 3 lists the volume layout used for the infrastructure
functions including user data
Table 3 Volume layout for hosting infrastructure components and user data
Volume name Size Purpose
Infrastructure 500 GB Storage for Active Directory SQL Server vCenter Server View Connection Server View Composer and File Server
UserSpace 2 TB Storage for User profiles and folder redirection space (Average 25 GB per user)
Along with the infrastructure volumes the storage array also provided shared storage for hosting the
virtual desktops The volume layout used for configuring the base image (View Composer Replica) and VDI
volumes on the array is shown in Table 4
17 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 4 Dell Storage PS4210XS layout for volumes hosting virtual desktops
Volume name Size Purpose
View-Replicas1 and 2 100 GB each Storage for base image for VDI deployment
VDI-Images1 through 8 500 GB each Storage for VDI VMs in VDI Cluster Each volume hosted 100 desktops
44 vSphere host network configuration VMware vSphere 55 hypervisor was installed on all servers The network configuration on each of those
hosts is described here Each vSphere host was configured with five virtual switches vSwitch0 vSwitch1
vSwitch2 vSwitch3 and vSwitch4 to separate different types of traffic on the system
Table 5 vSwitch configuration in vSphere hosts
vSwitch Description
vSwitch0 Management Network
vSwitch1 and vSwitch2 iSCSI SAN
vSwitch3 Fluid Cache VLAN
vSwitch4 VDI LAN
For additional information about individual vSwitch configuration refer to Appendix B in the Dell technical
white paper
45 Horizon view configuration Horizon View 60 was installed by using the documentation provided by VMware
Horizon View 601 installation documentation
httpswwwvmwarecomsupportpubsview_pubshtml
Table 6 Specific configuration used in the tests
Purpose Count Type Memory CPU
Horizon View Connection Servers
2 VM 16 GB 8nos
View Composer Server 1 VM 8 GB 8nos
18 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
46 Windows 7 VM configuration Following the guidelines from VMware and Login VSI the Windows 7 base image was generated based on
a generic base VM with the following properties
VMware Virtual Hardware version 8
Two virtual CPU
3 GB RAM with 15GB reserved
25 GB virtual hard drive
One virtual NIC connected to the VDI network
Windows 7 64-bit OS
Also the base image was customized by using the VMware Horizon with View Optimization Guide for
Windows 7 and Windows 8 available at this location httpwwwvmwarecomfilespdfVMware-View-
OptimizationGuideWindows7-ENpdf
19 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
5 Horizon view test methodology This section outlines the test objectives along with the test tools and criteria used to determine the
optimal virtual desktop density and best practices for deploying Horizon View on Dell Fluid Cache for SAN
for high IOPS type VDI environment
51 Test objectives As noted in Section 11 the test objectives were
Develop an optimal end-to-end infrastructure design for a Horizon View and vSpherendashbased high
user type of VDI solution deployed by using the Fluid Cache Compellent storage PowerEdge
servers and Dell Networking switches
Determine the performance at every layer of the VDI solution stack under high IOPS workload For
example desktops generating 80ndash90 IOPSVM at steady state
Determine the performance impact of peak IO activity such as boot and login storms
52 Test tools All tests were conducted by using Login VSI 40 as the workload generator and user experience analyzer
tool Login VSI is a benchmarking tool to measure the performance and scalability of centralized desktop
environments such as Server Based Computing (SBC) and VDI
Note More information can be found at the Login VSI website httpwwwloginvsicom
In addition to Login VSI Iometer is used in desktop VMs to simulate high IOPS conditions Iometer is
invoked in desktop VMs by using custom scripting of Login VSI workloads
Note More information can be found at the Iometer project website httpwwwiometerorg
521 Load generation First the ldquoMediumrdquo workload from Login VSI was used to simulate the standard user workload The
characteristics of the Medium workload are
Up to five applications are started simultaneously
Applications include Microsoft Internet Explorer Microsoft Word Microsoft Excel Microsoft
PowerPoint PDF reader 7-Zip compression software Movie player and FreeMind
After a session is started the medium workload repeats approximately after every 48 minutes
During a loop the response time is measured after every 3ndash4 minutes
Idle time is about two minutes in each 48-minute loop
Type rate is approximately 160 milliseconds per character
After the test by using Login VSI Medium was complete tests were rerun with Login VSI Medium and
Iometer in desktop VMs to simulate high IOPS VDI workload While the Login VSI Medium generates 8ndash10
20 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
IOPSVM the latter method was able to generate 80ndash90 IOPSVM For these tests each VM in the Horizon
view pool is created with standard LoginVSI contents and applications Also Iometer is installed on each
VM After the user logs in a customized logon script starts the Iometer with required IO specification (icf
file)
522 Monitoring tools The following monitoring tools were used
Dell Compellent Enterprise Manager for monitoring Fluid Cache and Compellent SC8000 storage
array performance
VMware vCenter statistics for vSphere performance
Login VSI Analyzer for end user performance statistics
Detailed performance metrics were captured from the storage arrays hypervisors virtual desktops and
the load generators during the tests
53 Test criteria The primary focus of the tests is to validate the 800 desktop high IOPS type of VDI architecture with
acceptable user experience by using Fluid Cache for SAN VDI configurations involve many components at
different layers ndash application hypervisor server network and storage As a result multiple metrics need to
be captured at different layers to ensure that the environment is healthy and performing optimally and
appropriately for all users
The specific test criteria are described in the following sections
531 Storage capacity and IO latency The typical industry standard latency limit for storage disk IO is 10 milliseconds Maintaining this limit
ensures good user application response times when there are no other bottlenecks at the infrastructure
layer In addition Dell recommends to maintain a 10 percent spare disk space on the storage array for
optimal performance
532 System utilization at the hypervisor Even though the primary focus of these tests was storage characterization additional metrics at the
hypervisor infrastructure layer were defined to ensure solution consistency These were
CPU utilization on any vSphere server must not exceed 85 percent
Minimal memory ballooning on the VMs
Total network bandwidth utilization must not exceed 90 percent on any one link
TCPIP storage network retransmissions should be less than 05 percent
21 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
533 Virtual desktop user experience Login VSI Analyzer was also used to gather metrics on the user experience at the virtual desktop layer to
ensure that all the desktops had acceptable levels of application performance Login VSI uses the VSImax
parameter to determine the maximum number of sessions that can be obtained from a deployed solution
The calculation methodology used in VSImax is available here
httpwwwloginvsicomdocumentationindexphptitle=Analyzing_Results
534 Test configuration A single virtual desktop pool was configured by using the VMware Horizon View Administrator interface
Each pool was built from a Windows 7 base image The Windows 7 configuration information is available
in Section 46
Desktop pool properties
Automatic Desktop Pool
Users are assigned using Floating assignments
View Storage Accelerator is enabled for all hosts with a refresh period of seven days
800 desktops were deployed across eight hosts (100 desktops a host)
Replica images were stored on a separate volume
22 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
6 Test results and analysis This section presents the results from the different Horizon View VDI characterization tests and the key
findings from each test The testing was focused on the high IOPS workload profile
61 Test scenarios The following tests were conducted to gather results and analysis on the solution stack
1 Boot storm Boot storms represent the worst-case scenario where many virtual desktops are
turned on at the same time and they all contend for the system resources simultaneously This test
was used to evaluate if the storage array hosting the desktops was capable of handling huge
variation in storage IO without causing significant impact on other services
2 Login storm Login storms also represent a high IOPS situation where many users are logging in to
their virtual desktops at the beginning of a workday or a shift In this test all the desktops were
pre-booted and left in an idle state for more than 20 minutes to let their IO settle before running
the Login VSI Medium workload to simulate users logging in to their virtual desktops
3 Steady state workload for standard users with normal IOPS After the login storm for the previous
test was completed the Login VSI Medium workload was allowed to run for at least one hour to
simulate the real-world scenario of users performing their daily tasks The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
4 Steady state workload for users with high IOPS The previous test was repeated with the Login
VSI Medium workload and Iometer scripts in desktop VMs as described in Section 521 to simulate
real-world heavy users performing their daily tasks with high IOPS The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
The following sections provide results from the boot storm login storm and steady state testing for the
Fluid Cache for SAN based VDI solution
23 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
62 Boot storm IO To simulate a boot storm the virtual desktops were reset simultaneously from the VMware vSphere client
Figure 6 shows the IO pattern on the Fluid Cache for the boot storm
Figure 6 SAN HQ data showing boot storm performance with Fluid Cache array
With 800 desktops the boot storm generated about 115000 total IOPS with a majority of them being
write operations All desktops were available for use in less than four minutes
24 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
63 Login storm and steady state for standard users (LoginVSI
Medium) Login VSI was programmed to start 800 virtual desktops over a period of about 60 minutes after pre-
booting the virtual desktops The peak IOPS during the login storm observed by the vSphere servers
hosting the desktops was about 6500 IOPS (8ndash10 IOPS a VM)
In a standard user environment login storms generate significantly more write IOPS than a boot storm or
steady state because of multiple factors such as
User profile activity
Starting operating system services on the desktop
First start of applications
After a virtual desktop has achieved a steady state after user login the Windows 7 OS has cached
applications in memory and does not need to access storage each time the application is started This
leads to lesser IOPS during the steady state Figure 7 here shows the various IO characteristics during the
login storm and steady state of these tests
25 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 7 IOPS and Cache Hit for the standard user test
On the Fluid Cache layer the maximum IOPS reached 6500 with cache-hit reaching 100 percent and
read-hit around 95 percent As shown in the Figure 8 here the throughput peaked at 98 MBps with a low
latency of less than 2 msec
26 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 8 Throughput and Latency for the standard user test
631 Server host performance During the login storm and steady state of the test the vSphere host CPU memory network and storage
performance were measured on all the servers that hosted the virtual desktops The performance of one
such vSphere server is given here The other vSphere servers had similar performance characteristics
Statistics for the vSphere hosts were captured by using VMware vCenter Server The figures here show the
CPU memory and network utilization for boot storm login storm and steady state of one of the vSphere
servers hosting the virtual desktops The results shown here are for a test run with 800 no standard user
desktops in the desktop pool
27 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 9 Average CPU performance per core on one vSphere host during login storm and steady state
Figure 10 Disk space usage during login storm and steady state
0
10
20
30
40
50
60
70
80
90
100
1020 1045 1110 1135 1200 1225
Per
cen
t
Time
CPU Performance
0
50
100
150
200
250
300
1020 1040 1100 1120 1140 1200 1220
GB
Time
Memory Performance
Granted Swap used Shared common
28 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 11 Overall network performance during login storm and steady state
Figure 12 Storage adapter performance during login storm and steady state
0
10000
20000
30000
40000
50000
60000
70000
1020 1045 1110 1135 1200 1225
kBp
s
Time
Network Performance
0
05
1
15
2
25
1020 1045 1110 1135 1200 1225
mSe
c
Time
Storage adaptor performance
29 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
The key observations from the statistics were
CPU utilization was less than the 85 percent threshold throughout the test
Active disk space usage was about 80 percent during the boost storm and about 60 percent
during login storm and steady state There was minimal-or no memory ballooning observed
Network utilization was about 45 percent which included all the networks such as iSCSI SAN VDI
LAN Management LAN and vMotion LAN
Average read- and write latencies at the storage adapter level were very close to the observed
latencies in Fluid Cache 2 msec
632 Monitoring user experience Figure 13 here shows the response time as experienced by each user as calculated by Login VSI The graph
clearly shows that the VSImax (Dynamic) value has not been reached and there were non-responsive or
inactive sessions This means that the array is capable of supporting the 1000 desktops and all users have
acceptable response times for applications that the user is has started
Figure 13 Login VSI user experience monitoring for 800 standard user desktops
30 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
633 Standard user test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SANndashbased VDI solution is able to host 800 virtual desktops and support
a standard user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only operations and
less than 2 percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to handle this login storm easily with low latency mdash it delivered the required 6500 IOPS with less
than 2 milliseconds of write latency with a 99 percent write VDI IO workload
64 Login storm and steady state with high IOPS (LoginVSI Medium +
Iometer) As mentioned earlier Iometer was used in desktop VMs alongside the Login VSI Medium workload to
simulate high IOPS type of VDI environment To mimic actual VDI workload profile the following Iometer
profile was used
20 KB block size 80 percent write 75 percent random with 25 msec burst delay
Figure 14 here shows the various IO characteristics during the login storm and steady state of these tests
Figure 14 IOPS and Cache Hit for the high IOPS test
On the Fluid Cache layer the maximum IOPS reached was approximately 72000 (or 90 IOPSVM) with
cache write-hit 100 percent and read-hit around 95 percent As shown in the Figure 15 the throughput
peaked at greater than 900 MBps with a peak latency of approximately 75 msec
31 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 15 Throughput and Latency for the high IOPS test
32 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
641 Server host performance Similar to the standard user test statistics for the vSphere hosts were captured by using VMware vCenter
Server during the high IOPS (heavy user) test also There are no significant differences in CPU disk space
and network utilization between standard users and heavy users The storage adapter latency is also
showing similar on hosts and observed on Fluid Cache
642 User experience monitoring Figure 16 here shows the response time as experienced by each user as calculated by Login VSI for the
heavy user test The graph shows that the VSImax (Dynamic) value was 796 indicating that the solution is
capable of supporting the 800 user high IOPS desktops with 90 IOPSVM
Figure 16 Login VSI user experience monitoring for 800 user high IOPS desktops
33 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
643 High IOPS (heavy user) test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SAN based VDI solution is able to host 800 virtual desktops and support a
high user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only and less than 2
percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to easily handle this login storm with low latency Subsequently it was able to handle 72000 IOPS
at high IOPS steady state with 90 IOPSVM with a maximum of 75 msec latency
34 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
7 Best practices This section provides the best practices derived from the testing and analysis in Section 6
71 Virtual Desktop Infrastructure This section provides best practices for the implementation of VDI using Dell Fluid Cache for SAN
711 Implement roaming profiles and folder redirection Dell recommends that all users in the VDI environment be configured with roaming profiles and folder
redirection This preserves user profiles and user data across boots while using non-persistent virtual
desktops
Also Dell recommends to use a high performance file service to provide the profile and folder redirection
A separate array may be used to host these volumes for best performance
712 Boot and login storm considerations Section 62 demonstrated the Fluid Cache for SAN performance under boot storm To avoid any potential
IO bursts because of boot storm and degraded user experience and performances Dell recommends that
all or portion of desktops be prebooted Connection brokers such as VMware Horizon View provide the
functionality to configure number of standby desktops
713 Windows 7 master image for desktop VMs Dell recommends that the operating system be customized in order to provide the best performance in a
VDI environment This includes disabling some services which may not be required This can improve
performance for the end user VMware has a specific set of recommendations and settings for Windows 7
and Windows 8 that allow for faster logins quicker screen refreshes and generally better performance
The VMware recommendations for Windows 7 and Windows 8 image optimization can be found here
httpwwwvmwarecomresourcestechresources10157
714 VDI Management infrastructure recommendations Dell recommends to have redundancy and load balancing for all VDI management services in the case of
VMware Horizon View solution as tested here the vSphere Server VMware Horizon View Servers and SQL
Servers Ideally these should be running on clustered hosts with VMware vSphere DRS (distributed
resource scheduler) and HA (high availability) enabled
72 Server host The vSphere servers hosting the infrastructure service providers and the virtual desktops are
recommended to be configured as follows
35 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Follow VMware and Dell best practices for installing and configuring vSphere
Separate virtual switches to segregate iSCSI SAN traffic VDI traffic vMotion traffic and Management
network traffic
Each network path must be assigned to a minimum of two physical NICs for high availability
VMware Knowledge Base article about best practices for installing vSphere 55
httpkbvmwarecomkb2052329
73 Network layer Dell recommends that at least two physical NICs on each vSphere server be dedicated to the VDI network
Use VLANs to segregate different types of network traffic on the same physical network In this case Dell
recommends to separate the infrastructure vMotion and VDI LAN traffic in to separate VLANs
Do not use VLANs to segregate iSCSI SAN and Fluide Cache traffic It is required that SAN and Cache traffic
be on separate dedicated physical network to provide the best performance
Virtual switches in vSphere have a default limit of 120 ports If the number of virtual desktops on each host
exceeds the available ports vSwitch properties should be changed to support the required number of
virtual desktops This change requires a restart of the host vSphere server
On iSCSI SAN switches Spanning tree must be disabled on switch ports connected to end devices for
server and storage ports The PortFast setting must be enabled in the switch configuration for these ports
Jumbo frames and Flow control (if the NICs support it) should be enabled for all components of the iSCSI
network
More information about configuring Dell Networking switches for use with Dell Storage iSCSI SANs is
available here
httpencommunitydellcomtechcenterstoragewwiki4250switch-configuration-guides-by-sisaspx
74 Storage The Dell SC storage arrays combined with Fluid Cache is an excellent platform for providing cost-effective
performance in VDI environments
Fluid Cache for SAN extends the power of Compellent intelligent data placement from the SAN to the
server By providing a single infrastructure for data at both high- and low ends of the performance
spectrum Fluid Cache for SAN with Storage Center 65 array software eliminates the tradeoffs between
server performance and full-featured SAN benefits such as reliability manageability and data protection
Dell recommends to have separate volumes for base image and virtual desktops This enables better
manageability of the volumes easier performance monitoring and allows easy future growth
Dell recommends to use a separate high performance file service to provide file shares for roaming
profiles and user shares
36 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
8 Conclusion The technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed by using a Horizon View VDI platform leveraging Dell Fluid Cache for SAN The storage IO
characteristics under various VDI workload scenarios (boot storm login storm and steady state) along
with performance characteristics throughout the VDI stack (for example vSphere server performance and
user experience) demonstrate the optimal configuration of the infrastructure used for this VDI
deployment For more information about Fluid Cache contact your Dell account manager
37 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
A Horizon view solution configuration
Table 7 Hardware components
Hardware components Description
Virtual Desktops 4 timesDell PowerEdge R720 Servers (Fluid Cache Providers)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
2times350 GB Dell Express Flash PCIe SSDs
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
4 x Dell PowerEdge R720 Servers (Fluid Cache Clients)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55 U2 on all R720 servers Windows 7 (64 Bit) VMs
Infrastructure Servers 2 x Dell PowerEdge R720 servers
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
96 GB RAM
2times300 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55U2 on all R720 servers VMs are loaded with Microsoft Windows 2008 R2
Active Directory
VMware Horizon View 60 Server 1
VMware Horizon View 60 Server 2
VMware vCenter Server 55 update 2
VMware Horizon View Composer
SQL Server
File Server
Login VSI Launchers 8 x Dell PowerEdge M610 servers
2timesIntelreg Xeonreg E-5503 200 GHz Processors
16 GB RAM
4times146 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57711 10GbE NIC
ESXi 51 installed on all R810 servers VMs are loaded with Microsoft Windows 7 64bit Each VM supports up to 30 Login VSI launcher sessions
38 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Network Management VDI LAN
1timesDell Force10 S55 1Gb Ethernet Switch
iSCSI SAN
1timesDell Force10 S4810 10Gb Ethernet Switch
Cache network
1timesDell Force10 S4810 10Gb Ethernet Switch
One Force10 S4810 switch might suffice for all the cache iSCSI SAN VDI LAN and management traffic
Storage 2timesDell Compellent SC8000 controllers 4times6Gb SAS 4-port PCI-E Full-height cards for back-end connectivity 2times10Gb iSCSI 2 port PCI-E Low-profile IO cards for front end connectivity 1timesDell Compellent SC200 disk enclosures 12times4TB NL-SAS 6Gb 72K 35rdquo drives
User Data Infrastructure VMs Virtual Desktops
Performance Monitoring
Dell Compellent Enterprise Manager Dell Fluid Cache for SAN performance monitoring tool () vCenter Performance monitoring Liquidware Stratusphere UX
Performance monitoring on Compellent arrays Fluid Cache performance monitoring Performance monitoring and capture at the ESXi host User experience monitoring on the virtual desktop
39 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 8 Software components
Software components Description Version
Dell Fluid Cache for SAN 20
Dell Compellent Storage Center 64
Dell Compellent Enterprise Manager 64
VMware Horizon View Server 60
VMware Horizon View Composer 60
VMware Horizon View Agent 60
VMware Horizon View Client 64-bit 60
VMware ESXi Hypervisor 55 U2
VMware vCenter Server 55 U2
Microsoft SQL Server 2008R2 Enterprise x64 105016001
Client VM OS Microsoft Windows 7 Enterprise x64 SP1
Management VM OS Microsoft Windows Server 2008 Enterprise R2 x64 SP1
Microsoft Office MS office 2010 Standard Service Pack 1
Login VSI Version 40
Iometer 20060727
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
9 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
3 Solution architecture The overall architecture of the VDI solution for the high IOPS environment is shown in the figure here
Figure 2 VDI solution architecture
31 Software Horizon view Horizon View is a VDI solution that includes a complete suite of tools for delivering desktops as a secure
and managed service from a centralized infrastructure A Horizon View infrastructure consists of many
different software network and hardware layer components This section presents an overview of the key
Horizon View components and technologies that are critical for successful design and deployment of the
VDI environment
10 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
311 Horizon view components A functional list of Horizon View components used in this solution is given in the table here
Table 1 Horizon View components
Component Description
Client Devices Personal computing devices used by end users to run the Horizon View Client These can include special end-point devices such as Dell Wyse end points mobile phones and PCs
Horizon View Connection Server
A software service that acts as a broker for client connections by authenticating and then directing the incoming user requests to the appropriate virtual desktop physical desktop or terminal server
Horizon View Client Software that is used to access the Horizon View desktops
Horizon View Agent A service that runs on all systems used as sources for Horizon View desktops and facilitates network communication between the Horizon View clients and the Horizon View server
Horizon View Administrator
A web-based administration platform for the Horizon View infrastructure components
vCenterreg Server Central administration platform for configuring provisioning and managing VMware virtualized data centers
Horizon View Composer
A service running with Horizon View servers used to create pools of virtual desktops from a shared-base image to reduce storage capacity requirements
312 Virtual desktops Virtual desktops can be classified in to two major categories persistent and non-persistent
Persistent desktop environment All configuration and personalization on the assigned desktop is kept for
the user-between sessions When using persistent desktops an administrator usually has to provision
additional storage along with other administrative requirements such as patching and upgrading of
individual desktops
Non-persistent desktop environment Users are dynamically assigned virtual desktop VMs from a pool of
resources during login This type of virtual desktop does not retain any information between sessions At
logoff all changes are simply discarded and the virtual desktop is returned to the original state Patching
and upgrading non-persistent desktops requires only making the change to the base image and refreshing
or recomposing the virtual desktop pool Thus these desktops are much easier to manage but lack the
potential for persistent user customization
11 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
313 Horizon view desktop pools A desktop pool is a term VMware uses to describe a collection of desktops that are managed as a single
entity by the Horizon View Administrator interface Horizon View desktop pools allow administrators to
group users depending on the type of service the user requires There are two types of pools ndash Automated
and Manual
In Horizon View an Automated Pool is a collection of VMs cloned from a base template while a Manual
pool is created by the Horizon View Manager from existing desktop sources physical or virtual For each
desktop in the Manual pool the administrator selects a desktop source to deliver Horizon View access to
the clients
VMware View Personas profile management features can be used to achieve persistent desktop-like
behavior on non-persistent desktops By using these features an administrator can design a user account
where the configuration settings are written to a remote profile that is stored separately from the virtual
desktop image files This reduces the need for additional management on individual virtual desktops while
still providing a customized user experience
314 Using linked clones Significant storage space savings and increased efficiencies in desktop VM provisioning and administration
are possible when using VMware-linked clones A linked clone is a duplicate VM that shares the same base
image with the original VM but has separate differential data disks to track the differences from the
original one Each linked clone functions as an independent desktop VM with its own unique identity
Because linked clones share the same base image they consume significantly less storage disk space than
a set of completely independent VM images Temporary system data and other data unique to each linked
clone desktop VM are written to separate differential data storage and these temporary changes are
discarded during restart andor user logoff Persistent data such as user profiles applications and user
data can be optionally redirected to a CIFS share With this model software maintenance updates
antivirus remediation and patches need to be applied only on the base image These base image changes
automatically take effect on all linked clones without affecting any user settings and data
To configure linked clones the administrator creates a snapshot of a parent VM image with the required
OS settings and software installed Horizon View Composer first creates a full replica (clone) of the parent
VM and then uses this replica to create linked clones The replica can be placed on the same data store as
the linked clones or on a separate data store
More information about configuring linked clones can be found in the ldquoCreating Desktop Poolsrdquo section of
the VMware Horizon View Online Library here
315 Hypervisor platform VMware vSphere 55 VMware vSphere 55 is the enterprise virtualization platform used for building VDI and cloud
infrastructures VMware vSphere 55 includes three major layers virtualization management and interface
The virtualization layer includes infrastructure and application services The management layer is central
12 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
for configuring provisioning and managing virtualized environments The interface layer includes the
vSphere client and the vSphere web client
Throughout the solution all VMware and Microsoft best practices and prerequisites for core services were
used (NTP DNS Active Directory and others)
32 Hardware Dell infrastructure Figure 3 shows the design of the infrastructure for the Horizon Viewndashbased high IOPS type VDI
deployment that leverages Fluid Cache
An eight-node vSphere server cluster is used to host the virtual desktops Each of these server nodes has a
direct-attached PCIe SSD that is added to the Fluid Cache pool thus making each server a Fluid Cache
Provider (a server contributing to the Fluid Cache capacity) The eight PCIe SSDs were distributed among
all the servers to better balance the load on the Fluid Cache server Fluid Cache server1 These servers
were connected by using a private caching network to provide the Fluid Cache functionality Also the
servers were connected through a separate managementVDI client network and a 10 GB Ethernet iSCSI
SAN network
Another two-node vSphere server cluster is used to host the VDI infrastructure VMs such as vCenter
server View Connection server View Composer server SQL Server and Active Directory etc These
infrastructure servers were connected to the management network and the iSCSI SAN network
The Compellent storage array for the solution has two controllers and a mix of Write Intensive (WI) SSDs
15K SAS HDDs and 72K NL-SAS HDDs to provide the optimal performance and capacity needed for the
solution
Two switches are stacked together for different networks to provide redundancy in the networking layer
Ideally 40 GB Ethernet switches are recommended for the cache network While 1 GB Ethernet switches
can be used for management network it is better to use 10 GB Ethernet switches combining management
and VDI client networks The same 10 GB Ethernet switches can be used for iSCSI SAN also (with different
network traffic segmented by VLANs) provided they have adequate bandwidth needed for the specific VDI
deployment
Information about how this reference architecture was developed ensuring the optimal utilization across
the servers switches and storage arrays is discussed later in the following sections of this technical white
paper
1 Fluid Cache does not require all servers to be a Fluid Cache Provider For example in this case four
servers could have two PCIe SSDs each This configuration with four Fluid Cache Provider and four Fluid Cache Client would have had same capacity for Fluid Cache pool and all eight servers could have taken advantage of Fluid Cache However the chosen configuration for the technical white paper provides better performance the because VDI application caching load is unforming distributed among all the available servers
13 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 3 Infrastructure Set-up for VDI Solution
1 Enterprise Manager Console 2 Management and VDI Client Network 3 vSphere Servers hosting virtual desktops 4 Cache network switches (2)
5 SAN switch 6 Storage Center controllers (2) 7 Storage Center expansion enclosures (2) 8 Server hosting VDI infrastructure VMs
(Server 1) (Server 2)
14 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
4 Solution configuration This section provides information about the solution configuration and test setup for hosting Horizon View
virtual desktops including infrastructure components networking and storage subsystems
41 Host design considerations The entire VDI solution was installed in two vSphere server clusters The clusters included
Figure 4 vSphere server clusters
Infrastructure Cluster Two Dell PowerEdge R720 servers hosting VMs for Active Directory
services VMware vCenter 55 server Horizon View Connection server (primary and secondary)
View Composer server Microsoft Windows Server 2012 R2 based file server and SQL Server 2012
R2
View Client Cluster Eight Dell PowerEdge R720 servers hosting the virtual desktops Each server
had
o 2times10 core Intel Xeon CPU E5-2690v2 300GHz
o 256 GB RAM
o 1times350 GB Dell Express Flash PCIe SSD
o 1timesMellanox Connect ndash X3 card
o 1timesDual-port Broadcom NetXtreme II BCM57810 10 Gigabit NIC
o 1timesQuad-port Broadcom NetXtreme BCM5720 Gigabit NIC
Along with the other servers the above servers 40 LoginVSI launcher VMs were used to generate VDI
workload They can be hosted by two PowerEdge R720 servers or equivalent for VDI load generation
purposes
15 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
42 Network design considerations Figure 5 here shows the network layout of one of the eight PowerEdge R720 servers with vSphere 55
installed
Figure 5 vSphere host network configuration
Three network switches are used in the Fluid Cache for VDI implementation One Force10 S55 1 GB switch
for all management traffic and VDI traffic The management traffic includes hosts and vSphere
management Compellent storage management and so on The networks are segregated by using VLANs
to separate different types of traffic
One Dell Force10 S4810 10 GB switch is used for Fluid Cache cache network which supports all the traffic
between cache layer on eight VDI VM hosts Another Force10 S4810 10 GB switch is used for iSCSI
network between infrastructure hosts VDI VM hosts and Compellent SC8000
Appendix B has extended information on the vSwitch configuration for each vSphere host
16 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
43 Dell Compellent SC8000 storage array configurations The storage used to host the virtual desktops was a Dell Compellent SC8000 array running Storage Center
Operating System (SCOS) 65 All two front-end ports were 10 GB iSCSI and all two back-end ports were
six GB serial-attached SCSI (SAS) The array used two external enclosures with Write Intensive (WI) SSDs
comprising Tier 1 and 15K SAS HDDs comprising Tier 2 for performance Also 72 NL-SAS drives were
used in Tier 3 to provide capacity for user data Table 2 summarizes the storage hardware configuration
Table 2 Storage hardware components
Storage role Type Qty Description
Controllers SC8000 2 System Center Operating System (SCOS) 65
Enclosures External 2 24 bay ndash 25rdquo disk drive enclosure
Ports Ethernet ndash 10 Gbps 2 Front end host connectivity
SAS - 6 Gbps 4 Back end drive connectivity
Drives 400 GB WI SSD 12 11 active with 1 hot spare
300 GB 15K SAS HDD
21 20 active with 1 hot spare
4 TB 72K NL-SAS HDD
12 11 active with 1 hot spare
The volumes created to host the virtual desktops took advantage of the Compellent Dynamic Capacity
technology for efficient capacity allocation Table 3 lists the volume layout used for the infrastructure
functions including user data
Table 3 Volume layout for hosting infrastructure components and user data
Volume name Size Purpose
Infrastructure 500 GB Storage for Active Directory SQL Server vCenter Server View Connection Server View Composer and File Server
UserSpace 2 TB Storage for User profiles and folder redirection space (Average 25 GB per user)
Along with the infrastructure volumes the storage array also provided shared storage for hosting the
virtual desktops The volume layout used for configuring the base image (View Composer Replica) and VDI
volumes on the array is shown in Table 4
17 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 4 Dell Storage PS4210XS layout for volumes hosting virtual desktops
Volume name Size Purpose
View-Replicas1 and 2 100 GB each Storage for base image for VDI deployment
VDI-Images1 through 8 500 GB each Storage for VDI VMs in VDI Cluster Each volume hosted 100 desktops
44 vSphere host network configuration VMware vSphere 55 hypervisor was installed on all servers The network configuration on each of those
hosts is described here Each vSphere host was configured with five virtual switches vSwitch0 vSwitch1
vSwitch2 vSwitch3 and vSwitch4 to separate different types of traffic on the system
Table 5 vSwitch configuration in vSphere hosts
vSwitch Description
vSwitch0 Management Network
vSwitch1 and vSwitch2 iSCSI SAN
vSwitch3 Fluid Cache VLAN
vSwitch4 VDI LAN
For additional information about individual vSwitch configuration refer to Appendix B in the Dell technical
white paper
45 Horizon view configuration Horizon View 60 was installed by using the documentation provided by VMware
Horizon View 601 installation documentation
httpswwwvmwarecomsupportpubsview_pubshtml
Table 6 Specific configuration used in the tests
Purpose Count Type Memory CPU
Horizon View Connection Servers
2 VM 16 GB 8nos
View Composer Server 1 VM 8 GB 8nos
18 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
46 Windows 7 VM configuration Following the guidelines from VMware and Login VSI the Windows 7 base image was generated based on
a generic base VM with the following properties
VMware Virtual Hardware version 8
Two virtual CPU
3 GB RAM with 15GB reserved
25 GB virtual hard drive
One virtual NIC connected to the VDI network
Windows 7 64-bit OS
Also the base image was customized by using the VMware Horizon with View Optimization Guide for
Windows 7 and Windows 8 available at this location httpwwwvmwarecomfilespdfVMware-View-
OptimizationGuideWindows7-ENpdf
19 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
5 Horizon view test methodology This section outlines the test objectives along with the test tools and criteria used to determine the
optimal virtual desktop density and best practices for deploying Horizon View on Dell Fluid Cache for SAN
for high IOPS type VDI environment
51 Test objectives As noted in Section 11 the test objectives were
Develop an optimal end-to-end infrastructure design for a Horizon View and vSpherendashbased high
user type of VDI solution deployed by using the Fluid Cache Compellent storage PowerEdge
servers and Dell Networking switches
Determine the performance at every layer of the VDI solution stack under high IOPS workload For
example desktops generating 80ndash90 IOPSVM at steady state
Determine the performance impact of peak IO activity such as boot and login storms
52 Test tools All tests were conducted by using Login VSI 40 as the workload generator and user experience analyzer
tool Login VSI is a benchmarking tool to measure the performance and scalability of centralized desktop
environments such as Server Based Computing (SBC) and VDI
Note More information can be found at the Login VSI website httpwwwloginvsicom
In addition to Login VSI Iometer is used in desktop VMs to simulate high IOPS conditions Iometer is
invoked in desktop VMs by using custom scripting of Login VSI workloads
Note More information can be found at the Iometer project website httpwwwiometerorg
521 Load generation First the ldquoMediumrdquo workload from Login VSI was used to simulate the standard user workload The
characteristics of the Medium workload are
Up to five applications are started simultaneously
Applications include Microsoft Internet Explorer Microsoft Word Microsoft Excel Microsoft
PowerPoint PDF reader 7-Zip compression software Movie player and FreeMind
After a session is started the medium workload repeats approximately after every 48 minutes
During a loop the response time is measured after every 3ndash4 minutes
Idle time is about two minutes in each 48-minute loop
Type rate is approximately 160 milliseconds per character
After the test by using Login VSI Medium was complete tests were rerun with Login VSI Medium and
Iometer in desktop VMs to simulate high IOPS VDI workload While the Login VSI Medium generates 8ndash10
20 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
IOPSVM the latter method was able to generate 80ndash90 IOPSVM For these tests each VM in the Horizon
view pool is created with standard LoginVSI contents and applications Also Iometer is installed on each
VM After the user logs in a customized logon script starts the Iometer with required IO specification (icf
file)
522 Monitoring tools The following monitoring tools were used
Dell Compellent Enterprise Manager for monitoring Fluid Cache and Compellent SC8000 storage
array performance
VMware vCenter statistics for vSphere performance
Login VSI Analyzer for end user performance statistics
Detailed performance metrics were captured from the storage arrays hypervisors virtual desktops and
the load generators during the tests
53 Test criteria The primary focus of the tests is to validate the 800 desktop high IOPS type of VDI architecture with
acceptable user experience by using Fluid Cache for SAN VDI configurations involve many components at
different layers ndash application hypervisor server network and storage As a result multiple metrics need to
be captured at different layers to ensure that the environment is healthy and performing optimally and
appropriately for all users
The specific test criteria are described in the following sections
531 Storage capacity and IO latency The typical industry standard latency limit for storage disk IO is 10 milliseconds Maintaining this limit
ensures good user application response times when there are no other bottlenecks at the infrastructure
layer In addition Dell recommends to maintain a 10 percent spare disk space on the storage array for
optimal performance
532 System utilization at the hypervisor Even though the primary focus of these tests was storage characterization additional metrics at the
hypervisor infrastructure layer were defined to ensure solution consistency These were
CPU utilization on any vSphere server must not exceed 85 percent
Minimal memory ballooning on the VMs
Total network bandwidth utilization must not exceed 90 percent on any one link
TCPIP storage network retransmissions should be less than 05 percent
21 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
533 Virtual desktop user experience Login VSI Analyzer was also used to gather metrics on the user experience at the virtual desktop layer to
ensure that all the desktops had acceptable levels of application performance Login VSI uses the VSImax
parameter to determine the maximum number of sessions that can be obtained from a deployed solution
The calculation methodology used in VSImax is available here
httpwwwloginvsicomdocumentationindexphptitle=Analyzing_Results
534 Test configuration A single virtual desktop pool was configured by using the VMware Horizon View Administrator interface
Each pool was built from a Windows 7 base image The Windows 7 configuration information is available
in Section 46
Desktop pool properties
Automatic Desktop Pool
Users are assigned using Floating assignments
View Storage Accelerator is enabled for all hosts with a refresh period of seven days
800 desktops were deployed across eight hosts (100 desktops a host)
Replica images were stored on a separate volume
22 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
6 Test results and analysis This section presents the results from the different Horizon View VDI characterization tests and the key
findings from each test The testing was focused on the high IOPS workload profile
61 Test scenarios The following tests were conducted to gather results and analysis on the solution stack
1 Boot storm Boot storms represent the worst-case scenario where many virtual desktops are
turned on at the same time and they all contend for the system resources simultaneously This test
was used to evaluate if the storage array hosting the desktops was capable of handling huge
variation in storage IO without causing significant impact on other services
2 Login storm Login storms also represent a high IOPS situation where many users are logging in to
their virtual desktops at the beginning of a workday or a shift In this test all the desktops were
pre-booted and left in an idle state for more than 20 minutes to let their IO settle before running
the Login VSI Medium workload to simulate users logging in to their virtual desktops
3 Steady state workload for standard users with normal IOPS After the login storm for the previous
test was completed the Login VSI Medium workload was allowed to run for at least one hour to
simulate the real-world scenario of users performing their daily tasks The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
4 Steady state workload for users with high IOPS The previous test was repeated with the Login
VSI Medium workload and Iometer scripts in desktop VMs as described in Section 521 to simulate
real-world heavy users performing their daily tasks with high IOPS The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
The following sections provide results from the boot storm login storm and steady state testing for the
Fluid Cache for SAN based VDI solution
23 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
62 Boot storm IO To simulate a boot storm the virtual desktops were reset simultaneously from the VMware vSphere client
Figure 6 shows the IO pattern on the Fluid Cache for the boot storm
Figure 6 SAN HQ data showing boot storm performance with Fluid Cache array
With 800 desktops the boot storm generated about 115000 total IOPS with a majority of them being
write operations All desktops were available for use in less than four minutes
24 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
63 Login storm and steady state for standard users (LoginVSI
Medium) Login VSI was programmed to start 800 virtual desktops over a period of about 60 minutes after pre-
booting the virtual desktops The peak IOPS during the login storm observed by the vSphere servers
hosting the desktops was about 6500 IOPS (8ndash10 IOPS a VM)
In a standard user environment login storms generate significantly more write IOPS than a boot storm or
steady state because of multiple factors such as
User profile activity
Starting operating system services on the desktop
First start of applications
After a virtual desktop has achieved a steady state after user login the Windows 7 OS has cached
applications in memory and does not need to access storage each time the application is started This
leads to lesser IOPS during the steady state Figure 7 here shows the various IO characteristics during the
login storm and steady state of these tests
25 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 7 IOPS and Cache Hit for the standard user test
On the Fluid Cache layer the maximum IOPS reached 6500 with cache-hit reaching 100 percent and
read-hit around 95 percent As shown in the Figure 8 here the throughput peaked at 98 MBps with a low
latency of less than 2 msec
26 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 8 Throughput and Latency for the standard user test
631 Server host performance During the login storm and steady state of the test the vSphere host CPU memory network and storage
performance were measured on all the servers that hosted the virtual desktops The performance of one
such vSphere server is given here The other vSphere servers had similar performance characteristics
Statistics for the vSphere hosts were captured by using VMware vCenter Server The figures here show the
CPU memory and network utilization for boot storm login storm and steady state of one of the vSphere
servers hosting the virtual desktops The results shown here are for a test run with 800 no standard user
desktops in the desktop pool
27 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 9 Average CPU performance per core on one vSphere host during login storm and steady state
Figure 10 Disk space usage during login storm and steady state
0
10
20
30
40
50
60
70
80
90
100
1020 1045 1110 1135 1200 1225
Per
cen
t
Time
CPU Performance
0
50
100
150
200
250
300
1020 1040 1100 1120 1140 1200 1220
GB
Time
Memory Performance
Granted Swap used Shared common
28 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 11 Overall network performance during login storm and steady state
Figure 12 Storage adapter performance during login storm and steady state
0
10000
20000
30000
40000
50000
60000
70000
1020 1045 1110 1135 1200 1225
kBp
s
Time
Network Performance
0
05
1
15
2
25
1020 1045 1110 1135 1200 1225
mSe
c
Time
Storage adaptor performance
29 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
The key observations from the statistics were
CPU utilization was less than the 85 percent threshold throughout the test
Active disk space usage was about 80 percent during the boost storm and about 60 percent
during login storm and steady state There was minimal-or no memory ballooning observed
Network utilization was about 45 percent which included all the networks such as iSCSI SAN VDI
LAN Management LAN and vMotion LAN
Average read- and write latencies at the storage adapter level were very close to the observed
latencies in Fluid Cache 2 msec
632 Monitoring user experience Figure 13 here shows the response time as experienced by each user as calculated by Login VSI The graph
clearly shows that the VSImax (Dynamic) value has not been reached and there were non-responsive or
inactive sessions This means that the array is capable of supporting the 1000 desktops and all users have
acceptable response times for applications that the user is has started
Figure 13 Login VSI user experience monitoring for 800 standard user desktops
30 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
633 Standard user test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SANndashbased VDI solution is able to host 800 virtual desktops and support
a standard user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only operations and
less than 2 percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to handle this login storm easily with low latency mdash it delivered the required 6500 IOPS with less
than 2 milliseconds of write latency with a 99 percent write VDI IO workload
64 Login storm and steady state with high IOPS (LoginVSI Medium +
Iometer) As mentioned earlier Iometer was used in desktop VMs alongside the Login VSI Medium workload to
simulate high IOPS type of VDI environment To mimic actual VDI workload profile the following Iometer
profile was used
20 KB block size 80 percent write 75 percent random with 25 msec burst delay
Figure 14 here shows the various IO characteristics during the login storm and steady state of these tests
Figure 14 IOPS and Cache Hit for the high IOPS test
On the Fluid Cache layer the maximum IOPS reached was approximately 72000 (or 90 IOPSVM) with
cache write-hit 100 percent and read-hit around 95 percent As shown in the Figure 15 the throughput
peaked at greater than 900 MBps with a peak latency of approximately 75 msec
31 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 15 Throughput and Latency for the high IOPS test
32 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
641 Server host performance Similar to the standard user test statistics for the vSphere hosts were captured by using VMware vCenter
Server during the high IOPS (heavy user) test also There are no significant differences in CPU disk space
and network utilization between standard users and heavy users The storage adapter latency is also
showing similar on hosts and observed on Fluid Cache
642 User experience monitoring Figure 16 here shows the response time as experienced by each user as calculated by Login VSI for the
heavy user test The graph shows that the VSImax (Dynamic) value was 796 indicating that the solution is
capable of supporting the 800 user high IOPS desktops with 90 IOPSVM
Figure 16 Login VSI user experience monitoring for 800 user high IOPS desktops
33 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
643 High IOPS (heavy user) test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SAN based VDI solution is able to host 800 virtual desktops and support a
high user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only and less than 2
percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to easily handle this login storm with low latency Subsequently it was able to handle 72000 IOPS
at high IOPS steady state with 90 IOPSVM with a maximum of 75 msec latency
34 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
7 Best practices This section provides the best practices derived from the testing and analysis in Section 6
71 Virtual Desktop Infrastructure This section provides best practices for the implementation of VDI using Dell Fluid Cache for SAN
711 Implement roaming profiles and folder redirection Dell recommends that all users in the VDI environment be configured with roaming profiles and folder
redirection This preserves user profiles and user data across boots while using non-persistent virtual
desktops
Also Dell recommends to use a high performance file service to provide the profile and folder redirection
A separate array may be used to host these volumes for best performance
712 Boot and login storm considerations Section 62 demonstrated the Fluid Cache for SAN performance under boot storm To avoid any potential
IO bursts because of boot storm and degraded user experience and performances Dell recommends that
all or portion of desktops be prebooted Connection brokers such as VMware Horizon View provide the
functionality to configure number of standby desktops
713 Windows 7 master image for desktop VMs Dell recommends that the operating system be customized in order to provide the best performance in a
VDI environment This includes disabling some services which may not be required This can improve
performance for the end user VMware has a specific set of recommendations and settings for Windows 7
and Windows 8 that allow for faster logins quicker screen refreshes and generally better performance
The VMware recommendations for Windows 7 and Windows 8 image optimization can be found here
httpwwwvmwarecomresourcestechresources10157
714 VDI Management infrastructure recommendations Dell recommends to have redundancy and load balancing for all VDI management services in the case of
VMware Horizon View solution as tested here the vSphere Server VMware Horizon View Servers and SQL
Servers Ideally these should be running on clustered hosts with VMware vSphere DRS (distributed
resource scheduler) and HA (high availability) enabled
72 Server host The vSphere servers hosting the infrastructure service providers and the virtual desktops are
recommended to be configured as follows
35 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Follow VMware and Dell best practices for installing and configuring vSphere
Separate virtual switches to segregate iSCSI SAN traffic VDI traffic vMotion traffic and Management
network traffic
Each network path must be assigned to a minimum of two physical NICs for high availability
VMware Knowledge Base article about best practices for installing vSphere 55
httpkbvmwarecomkb2052329
73 Network layer Dell recommends that at least two physical NICs on each vSphere server be dedicated to the VDI network
Use VLANs to segregate different types of network traffic on the same physical network In this case Dell
recommends to separate the infrastructure vMotion and VDI LAN traffic in to separate VLANs
Do not use VLANs to segregate iSCSI SAN and Fluide Cache traffic It is required that SAN and Cache traffic
be on separate dedicated physical network to provide the best performance
Virtual switches in vSphere have a default limit of 120 ports If the number of virtual desktops on each host
exceeds the available ports vSwitch properties should be changed to support the required number of
virtual desktops This change requires a restart of the host vSphere server
On iSCSI SAN switches Spanning tree must be disabled on switch ports connected to end devices for
server and storage ports The PortFast setting must be enabled in the switch configuration for these ports
Jumbo frames and Flow control (if the NICs support it) should be enabled for all components of the iSCSI
network
More information about configuring Dell Networking switches for use with Dell Storage iSCSI SANs is
available here
httpencommunitydellcomtechcenterstoragewwiki4250switch-configuration-guides-by-sisaspx
74 Storage The Dell SC storage arrays combined with Fluid Cache is an excellent platform for providing cost-effective
performance in VDI environments
Fluid Cache for SAN extends the power of Compellent intelligent data placement from the SAN to the
server By providing a single infrastructure for data at both high- and low ends of the performance
spectrum Fluid Cache for SAN with Storage Center 65 array software eliminates the tradeoffs between
server performance and full-featured SAN benefits such as reliability manageability and data protection
Dell recommends to have separate volumes for base image and virtual desktops This enables better
manageability of the volumes easier performance monitoring and allows easy future growth
Dell recommends to use a separate high performance file service to provide file shares for roaming
profiles and user shares
36 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
8 Conclusion The technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed by using a Horizon View VDI platform leveraging Dell Fluid Cache for SAN The storage IO
characteristics under various VDI workload scenarios (boot storm login storm and steady state) along
with performance characteristics throughout the VDI stack (for example vSphere server performance and
user experience) demonstrate the optimal configuration of the infrastructure used for this VDI
deployment For more information about Fluid Cache contact your Dell account manager
37 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
A Horizon view solution configuration
Table 7 Hardware components
Hardware components Description
Virtual Desktops 4 timesDell PowerEdge R720 Servers (Fluid Cache Providers)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
2times350 GB Dell Express Flash PCIe SSDs
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
4 x Dell PowerEdge R720 Servers (Fluid Cache Clients)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55 U2 on all R720 servers Windows 7 (64 Bit) VMs
Infrastructure Servers 2 x Dell PowerEdge R720 servers
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
96 GB RAM
2times300 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55U2 on all R720 servers VMs are loaded with Microsoft Windows 2008 R2
Active Directory
VMware Horizon View 60 Server 1
VMware Horizon View 60 Server 2
VMware vCenter Server 55 update 2
VMware Horizon View Composer
SQL Server
File Server
Login VSI Launchers 8 x Dell PowerEdge M610 servers
2timesIntelreg Xeonreg E-5503 200 GHz Processors
16 GB RAM
4times146 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57711 10GbE NIC
ESXi 51 installed on all R810 servers VMs are loaded with Microsoft Windows 7 64bit Each VM supports up to 30 Login VSI launcher sessions
38 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Network Management VDI LAN
1timesDell Force10 S55 1Gb Ethernet Switch
iSCSI SAN
1timesDell Force10 S4810 10Gb Ethernet Switch
Cache network
1timesDell Force10 S4810 10Gb Ethernet Switch
One Force10 S4810 switch might suffice for all the cache iSCSI SAN VDI LAN and management traffic
Storage 2timesDell Compellent SC8000 controllers 4times6Gb SAS 4-port PCI-E Full-height cards for back-end connectivity 2times10Gb iSCSI 2 port PCI-E Low-profile IO cards for front end connectivity 1timesDell Compellent SC200 disk enclosures 12times4TB NL-SAS 6Gb 72K 35rdquo drives
User Data Infrastructure VMs Virtual Desktops
Performance Monitoring
Dell Compellent Enterprise Manager Dell Fluid Cache for SAN performance monitoring tool () vCenter Performance monitoring Liquidware Stratusphere UX
Performance monitoring on Compellent arrays Fluid Cache performance monitoring Performance monitoring and capture at the ESXi host User experience monitoring on the virtual desktop
39 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 8 Software components
Software components Description Version
Dell Fluid Cache for SAN 20
Dell Compellent Storage Center 64
Dell Compellent Enterprise Manager 64
VMware Horizon View Server 60
VMware Horizon View Composer 60
VMware Horizon View Agent 60
VMware Horizon View Client 64-bit 60
VMware ESXi Hypervisor 55 U2
VMware vCenter Server 55 U2
Microsoft SQL Server 2008R2 Enterprise x64 105016001
Client VM OS Microsoft Windows 7 Enterprise x64 SP1
Management VM OS Microsoft Windows Server 2008 Enterprise R2 x64 SP1
Microsoft Office MS office 2010 Standard Service Pack 1
Login VSI Version 40
Iometer 20060727
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
10 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
311 Horizon view components A functional list of Horizon View components used in this solution is given in the table here
Table 1 Horizon View components
Component Description
Client Devices Personal computing devices used by end users to run the Horizon View Client These can include special end-point devices such as Dell Wyse end points mobile phones and PCs
Horizon View Connection Server
A software service that acts as a broker for client connections by authenticating and then directing the incoming user requests to the appropriate virtual desktop physical desktop or terminal server
Horizon View Client Software that is used to access the Horizon View desktops
Horizon View Agent A service that runs on all systems used as sources for Horizon View desktops and facilitates network communication between the Horizon View clients and the Horizon View server
Horizon View Administrator
A web-based administration platform for the Horizon View infrastructure components
vCenterreg Server Central administration platform for configuring provisioning and managing VMware virtualized data centers
Horizon View Composer
A service running with Horizon View servers used to create pools of virtual desktops from a shared-base image to reduce storage capacity requirements
312 Virtual desktops Virtual desktops can be classified in to two major categories persistent and non-persistent
Persistent desktop environment All configuration and personalization on the assigned desktop is kept for
the user-between sessions When using persistent desktops an administrator usually has to provision
additional storage along with other administrative requirements such as patching and upgrading of
individual desktops
Non-persistent desktop environment Users are dynamically assigned virtual desktop VMs from a pool of
resources during login This type of virtual desktop does not retain any information between sessions At
logoff all changes are simply discarded and the virtual desktop is returned to the original state Patching
and upgrading non-persistent desktops requires only making the change to the base image and refreshing
or recomposing the virtual desktop pool Thus these desktops are much easier to manage but lack the
potential for persistent user customization
11 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
313 Horizon view desktop pools A desktop pool is a term VMware uses to describe a collection of desktops that are managed as a single
entity by the Horizon View Administrator interface Horizon View desktop pools allow administrators to
group users depending on the type of service the user requires There are two types of pools ndash Automated
and Manual
In Horizon View an Automated Pool is a collection of VMs cloned from a base template while a Manual
pool is created by the Horizon View Manager from existing desktop sources physical or virtual For each
desktop in the Manual pool the administrator selects a desktop source to deliver Horizon View access to
the clients
VMware View Personas profile management features can be used to achieve persistent desktop-like
behavior on non-persistent desktops By using these features an administrator can design a user account
where the configuration settings are written to a remote profile that is stored separately from the virtual
desktop image files This reduces the need for additional management on individual virtual desktops while
still providing a customized user experience
314 Using linked clones Significant storage space savings and increased efficiencies in desktop VM provisioning and administration
are possible when using VMware-linked clones A linked clone is a duplicate VM that shares the same base
image with the original VM but has separate differential data disks to track the differences from the
original one Each linked clone functions as an independent desktop VM with its own unique identity
Because linked clones share the same base image they consume significantly less storage disk space than
a set of completely independent VM images Temporary system data and other data unique to each linked
clone desktop VM are written to separate differential data storage and these temporary changes are
discarded during restart andor user logoff Persistent data such as user profiles applications and user
data can be optionally redirected to a CIFS share With this model software maintenance updates
antivirus remediation and patches need to be applied only on the base image These base image changes
automatically take effect on all linked clones without affecting any user settings and data
To configure linked clones the administrator creates a snapshot of a parent VM image with the required
OS settings and software installed Horizon View Composer first creates a full replica (clone) of the parent
VM and then uses this replica to create linked clones The replica can be placed on the same data store as
the linked clones or on a separate data store
More information about configuring linked clones can be found in the ldquoCreating Desktop Poolsrdquo section of
the VMware Horizon View Online Library here
315 Hypervisor platform VMware vSphere 55 VMware vSphere 55 is the enterprise virtualization platform used for building VDI and cloud
infrastructures VMware vSphere 55 includes three major layers virtualization management and interface
The virtualization layer includes infrastructure and application services The management layer is central
12 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
for configuring provisioning and managing virtualized environments The interface layer includes the
vSphere client and the vSphere web client
Throughout the solution all VMware and Microsoft best practices and prerequisites for core services were
used (NTP DNS Active Directory and others)
32 Hardware Dell infrastructure Figure 3 shows the design of the infrastructure for the Horizon Viewndashbased high IOPS type VDI
deployment that leverages Fluid Cache
An eight-node vSphere server cluster is used to host the virtual desktops Each of these server nodes has a
direct-attached PCIe SSD that is added to the Fluid Cache pool thus making each server a Fluid Cache
Provider (a server contributing to the Fluid Cache capacity) The eight PCIe SSDs were distributed among
all the servers to better balance the load on the Fluid Cache server Fluid Cache server1 These servers
were connected by using a private caching network to provide the Fluid Cache functionality Also the
servers were connected through a separate managementVDI client network and a 10 GB Ethernet iSCSI
SAN network
Another two-node vSphere server cluster is used to host the VDI infrastructure VMs such as vCenter
server View Connection server View Composer server SQL Server and Active Directory etc These
infrastructure servers were connected to the management network and the iSCSI SAN network
The Compellent storage array for the solution has two controllers and a mix of Write Intensive (WI) SSDs
15K SAS HDDs and 72K NL-SAS HDDs to provide the optimal performance and capacity needed for the
solution
Two switches are stacked together for different networks to provide redundancy in the networking layer
Ideally 40 GB Ethernet switches are recommended for the cache network While 1 GB Ethernet switches
can be used for management network it is better to use 10 GB Ethernet switches combining management
and VDI client networks The same 10 GB Ethernet switches can be used for iSCSI SAN also (with different
network traffic segmented by VLANs) provided they have adequate bandwidth needed for the specific VDI
deployment
Information about how this reference architecture was developed ensuring the optimal utilization across
the servers switches and storage arrays is discussed later in the following sections of this technical white
paper
1 Fluid Cache does not require all servers to be a Fluid Cache Provider For example in this case four
servers could have two PCIe SSDs each This configuration with four Fluid Cache Provider and four Fluid Cache Client would have had same capacity for Fluid Cache pool and all eight servers could have taken advantage of Fluid Cache However the chosen configuration for the technical white paper provides better performance the because VDI application caching load is unforming distributed among all the available servers
13 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 3 Infrastructure Set-up for VDI Solution
1 Enterprise Manager Console 2 Management and VDI Client Network 3 vSphere Servers hosting virtual desktops 4 Cache network switches (2)
5 SAN switch 6 Storage Center controllers (2) 7 Storage Center expansion enclosures (2) 8 Server hosting VDI infrastructure VMs
(Server 1) (Server 2)
14 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
4 Solution configuration This section provides information about the solution configuration and test setup for hosting Horizon View
virtual desktops including infrastructure components networking and storage subsystems
41 Host design considerations The entire VDI solution was installed in two vSphere server clusters The clusters included
Figure 4 vSphere server clusters
Infrastructure Cluster Two Dell PowerEdge R720 servers hosting VMs for Active Directory
services VMware vCenter 55 server Horizon View Connection server (primary and secondary)
View Composer server Microsoft Windows Server 2012 R2 based file server and SQL Server 2012
R2
View Client Cluster Eight Dell PowerEdge R720 servers hosting the virtual desktops Each server
had
o 2times10 core Intel Xeon CPU E5-2690v2 300GHz
o 256 GB RAM
o 1times350 GB Dell Express Flash PCIe SSD
o 1timesMellanox Connect ndash X3 card
o 1timesDual-port Broadcom NetXtreme II BCM57810 10 Gigabit NIC
o 1timesQuad-port Broadcom NetXtreme BCM5720 Gigabit NIC
Along with the other servers the above servers 40 LoginVSI launcher VMs were used to generate VDI
workload They can be hosted by two PowerEdge R720 servers or equivalent for VDI load generation
purposes
15 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
42 Network design considerations Figure 5 here shows the network layout of one of the eight PowerEdge R720 servers with vSphere 55
installed
Figure 5 vSphere host network configuration
Three network switches are used in the Fluid Cache for VDI implementation One Force10 S55 1 GB switch
for all management traffic and VDI traffic The management traffic includes hosts and vSphere
management Compellent storage management and so on The networks are segregated by using VLANs
to separate different types of traffic
One Dell Force10 S4810 10 GB switch is used for Fluid Cache cache network which supports all the traffic
between cache layer on eight VDI VM hosts Another Force10 S4810 10 GB switch is used for iSCSI
network between infrastructure hosts VDI VM hosts and Compellent SC8000
Appendix B has extended information on the vSwitch configuration for each vSphere host
16 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
43 Dell Compellent SC8000 storage array configurations The storage used to host the virtual desktops was a Dell Compellent SC8000 array running Storage Center
Operating System (SCOS) 65 All two front-end ports were 10 GB iSCSI and all two back-end ports were
six GB serial-attached SCSI (SAS) The array used two external enclosures with Write Intensive (WI) SSDs
comprising Tier 1 and 15K SAS HDDs comprising Tier 2 for performance Also 72 NL-SAS drives were
used in Tier 3 to provide capacity for user data Table 2 summarizes the storage hardware configuration
Table 2 Storage hardware components
Storage role Type Qty Description
Controllers SC8000 2 System Center Operating System (SCOS) 65
Enclosures External 2 24 bay ndash 25rdquo disk drive enclosure
Ports Ethernet ndash 10 Gbps 2 Front end host connectivity
SAS - 6 Gbps 4 Back end drive connectivity
Drives 400 GB WI SSD 12 11 active with 1 hot spare
300 GB 15K SAS HDD
21 20 active with 1 hot spare
4 TB 72K NL-SAS HDD
12 11 active with 1 hot spare
The volumes created to host the virtual desktops took advantage of the Compellent Dynamic Capacity
technology for efficient capacity allocation Table 3 lists the volume layout used for the infrastructure
functions including user data
Table 3 Volume layout for hosting infrastructure components and user data
Volume name Size Purpose
Infrastructure 500 GB Storage for Active Directory SQL Server vCenter Server View Connection Server View Composer and File Server
UserSpace 2 TB Storage for User profiles and folder redirection space (Average 25 GB per user)
Along with the infrastructure volumes the storage array also provided shared storage for hosting the
virtual desktops The volume layout used for configuring the base image (View Composer Replica) and VDI
volumes on the array is shown in Table 4
17 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 4 Dell Storage PS4210XS layout for volumes hosting virtual desktops
Volume name Size Purpose
View-Replicas1 and 2 100 GB each Storage for base image for VDI deployment
VDI-Images1 through 8 500 GB each Storage for VDI VMs in VDI Cluster Each volume hosted 100 desktops
44 vSphere host network configuration VMware vSphere 55 hypervisor was installed on all servers The network configuration on each of those
hosts is described here Each vSphere host was configured with five virtual switches vSwitch0 vSwitch1
vSwitch2 vSwitch3 and vSwitch4 to separate different types of traffic on the system
Table 5 vSwitch configuration in vSphere hosts
vSwitch Description
vSwitch0 Management Network
vSwitch1 and vSwitch2 iSCSI SAN
vSwitch3 Fluid Cache VLAN
vSwitch4 VDI LAN
For additional information about individual vSwitch configuration refer to Appendix B in the Dell technical
white paper
45 Horizon view configuration Horizon View 60 was installed by using the documentation provided by VMware
Horizon View 601 installation documentation
httpswwwvmwarecomsupportpubsview_pubshtml
Table 6 Specific configuration used in the tests
Purpose Count Type Memory CPU
Horizon View Connection Servers
2 VM 16 GB 8nos
View Composer Server 1 VM 8 GB 8nos
18 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
46 Windows 7 VM configuration Following the guidelines from VMware and Login VSI the Windows 7 base image was generated based on
a generic base VM with the following properties
VMware Virtual Hardware version 8
Two virtual CPU
3 GB RAM with 15GB reserved
25 GB virtual hard drive
One virtual NIC connected to the VDI network
Windows 7 64-bit OS
Also the base image was customized by using the VMware Horizon with View Optimization Guide for
Windows 7 and Windows 8 available at this location httpwwwvmwarecomfilespdfVMware-View-
OptimizationGuideWindows7-ENpdf
19 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
5 Horizon view test methodology This section outlines the test objectives along with the test tools and criteria used to determine the
optimal virtual desktop density and best practices for deploying Horizon View on Dell Fluid Cache for SAN
for high IOPS type VDI environment
51 Test objectives As noted in Section 11 the test objectives were
Develop an optimal end-to-end infrastructure design for a Horizon View and vSpherendashbased high
user type of VDI solution deployed by using the Fluid Cache Compellent storage PowerEdge
servers and Dell Networking switches
Determine the performance at every layer of the VDI solution stack under high IOPS workload For
example desktops generating 80ndash90 IOPSVM at steady state
Determine the performance impact of peak IO activity such as boot and login storms
52 Test tools All tests were conducted by using Login VSI 40 as the workload generator and user experience analyzer
tool Login VSI is a benchmarking tool to measure the performance and scalability of centralized desktop
environments such as Server Based Computing (SBC) and VDI
Note More information can be found at the Login VSI website httpwwwloginvsicom
In addition to Login VSI Iometer is used in desktop VMs to simulate high IOPS conditions Iometer is
invoked in desktop VMs by using custom scripting of Login VSI workloads
Note More information can be found at the Iometer project website httpwwwiometerorg
521 Load generation First the ldquoMediumrdquo workload from Login VSI was used to simulate the standard user workload The
characteristics of the Medium workload are
Up to five applications are started simultaneously
Applications include Microsoft Internet Explorer Microsoft Word Microsoft Excel Microsoft
PowerPoint PDF reader 7-Zip compression software Movie player and FreeMind
After a session is started the medium workload repeats approximately after every 48 minutes
During a loop the response time is measured after every 3ndash4 minutes
Idle time is about two minutes in each 48-minute loop
Type rate is approximately 160 milliseconds per character
After the test by using Login VSI Medium was complete tests were rerun with Login VSI Medium and
Iometer in desktop VMs to simulate high IOPS VDI workload While the Login VSI Medium generates 8ndash10
20 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
IOPSVM the latter method was able to generate 80ndash90 IOPSVM For these tests each VM in the Horizon
view pool is created with standard LoginVSI contents and applications Also Iometer is installed on each
VM After the user logs in a customized logon script starts the Iometer with required IO specification (icf
file)
522 Monitoring tools The following monitoring tools were used
Dell Compellent Enterprise Manager for monitoring Fluid Cache and Compellent SC8000 storage
array performance
VMware vCenter statistics for vSphere performance
Login VSI Analyzer for end user performance statistics
Detailed performance metrics were captured from the storage arrays hypervisors virtual desktops and
the load generators during the tests
53 Test criteria The primary focus of the tests is to validate the 800 desktop high IOPS type of VDI architecture with
acceptable user experience by using Fluid Cache for SAN VDI configurations involve many components at
different layers ndash application hypervisor server network and storage As a result multiple metrics need to
be captured at different layers to ensure that the environment is healthy and performing optimally and
appropriately for all users
The specific test criteria are described in the following sections
531 Storage capacity and IO latency The typical industry standard latency limit for storage disk IO is 10 milliseconds Maintaining this limit
ensures good user application response times when there are no other bottlenecks at the infrastructure
layer In addition Dell recommends to maintain a 10 percent spare disk space on the storage array for
optimal performance
532 System utilization at the hypervisor Even though the primary focus of these tests was storage characterization additional metrics at the
hypervisor infrastructure layer were defined to ensure solution consistency These were
CPU utilization on any vSphere server must not exceed 85 percent
Minimal memory ballooning on the VMs
Total network bandwidth utilization must not exceed 90 percent on any one link
TCPIP storage network retransmissions should be less than 05 percent
21 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
533 Virtual desktop user experience Login VSI Analyzer was also used to gather metrics on the user experience at the virtual desktop layer to
ensure that all the desktops had acceptable levels of application performance Login VSI uses the VSImax
parameter to determine the maximum number of sessions that can be obtained from a deployed solution
The calculation methodology used in VSImax is available here
httpwwwloginvsicomdocumentationindexphptitle=Analyzing_Results
534 Test configuration A single virtual desktop pool was configured by using the VMware Horizon View Administrator interface
Each pool was built from a Windows 7 base image The Windows 7 configuration information is available
in Section 46
Desktop pool properties
Automatic Desktop Pool
Users are assigned using Floating assignments
View Storage Accelerator is enabled for all hosts with a refresh period of seven days
800 desktops were deployed across eight hosts (100 desktops a host)
Replica images were stored on a separate volume
22 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
6 Test results and analysis This section presents the results from the different Horizon View VDI characterization tests and the key
findings from each test The testing was focused on the high IOPS workload profile
61 Test scenarios The following tests were conducted to gather results and analysis on the solution stack
1 Boot storm Boot storms represent the worst-case scenario where many virtual desktops are
turned on at the same time and they all contend for the system resources simultaneously This test
was used to evaluate if the storage array hosting the desktops was capable of handling huge
variation in storage IO without causing significant impact on other services
2 Login storm Login storms also represent a high IOPS situation where many users are logging in to
their virtual desktops at the beginning of a workday or a shift In this test all the desktops were
pre-booted and left in an idle state for more than 20 minutes to let their IO settle before running
the Login VSI Medium workload to simulate users logging in to their virtual desktops
3 Steady state workload for standard users with normal IOPS After the login storm for the previous
test was completed the Login VSI Medium workload was allowed to run for at least one hour to
simulate the real-world scenario of users performing their daily tasks The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
4 Steady state workload for users with high IOPS The previous test was repeated with the Login
VSI Medium workload and Iometer scripts in desktop VMs as described in Section 521 to simulate
real-world heavy users performing their daily tasks with high IOPS The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
The following sections provide results from the boot storm login storm and steady state testing for the
Fluid Cache for SAN based VDI solution
23 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
62 Boot storm IO To simulate a boot storm the virtual desktops were reset simultaneously from the VMware vSphere client
Figure 6 shows the IO pattern on the Fluid Cache for the boot storm
Figure 6 SAN HQ data showing boot storm performance with Fluid Cache array
With 800 desktops the boot storm generated about 115000 total IOPS with a majority of them being
write operations All desktops were available for use in less than four minutes
24 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
63 Login storm and steady state for standard users (LoginVSI
Medium) Login VSI was programmed to start 800 virtual desktops over a period of about 60 minutes after pre-
booting the virtual desktops The peak IOPS during the login storm observed by the vSphere servers
hosting the desktops was about 6500 IOPS (8ndash10 IOPS a VM)
In a standard user environment login storms generate significantly more write IOPS than a boot storm or
steady state because of multiple factors such as
User profile activity
Starting operating system services on the desktop
First start of applications
After a virtual desktop has achieved a steady state after user login the Windows 7 OS has cached
applications in memory and does not need to access storage each time the application is started This
leads to lesser IOPS during the steady state Figure 7 here shows the various IO characteristics during the
login storm and steady state of these tests
25 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 7 IOPS and Cache Hit for the standard user test
On the Fluid Cache layer the maximum IOPS reached 6500 with cache-hit reaching 100 percent and
read-hit around 95 percent As shown in the Figure 8 here the throughput peaked at 98 MBps with a low
latency of less than 2 msec
26 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 8 Throughput and Latency for the standard user test
631 Server host performance During the login storm and steady state of the test the vSphere host CPU memory network and storage
performance were measured on all the servers that hosted the virtual desktops The performance of one
such vSphere server is given here The other vSphere servers had similar performance characteristics
Statistics for the vSphere hosts were captured by using VMware vCenter Server The figures here show the
CPU memory and network utilization for boot storm login storm and steady state of one of the vSphere
servers hosting the virtual desktops The results shown here are for a test run with 800 no standard user
desktops in the desktop pool
27 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 9 Average CPU performance per core on one vSphere host during login storm and steady state
Figure 10 Disk space usage during login storm and steady state
0
10
20
30
40
50
60
70
80
90
100
1020 1045 1110 1135 1200 1225
Per
cen
t
Time
CPU Performance
0
50
100
150
200
250
300
1020 1040 1100 1120 1140 1200 1220
GB
Time
Memory Performance
Granted Swap used Shared common
28 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 11 Overall network performance during login storm and steady state
Figure 12 Storage adapter performance during login storm and steady state
0
10000
20000
30000
40000
50000
60000
70000
1020 1045 1110 1135 1200 1225
kBp
s
Time
Network Performance
0
05
1
15
2
25
1020 1045 1110 1135 1200 1225
mSe
c
Time
Storage adaptor performance
29 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
The key observations from the statistics were
CPU utilization was less than the 85 percent threshold throughout the test
Active disk space usage was about 80 percent during the boost storm and about 60 percent
during login storm and steady state There was minimal-or no memory ballooning observed
Network utilization was about 45 percent which included all the networks such as iSCSI SAN VDI
LAN Management LAN and vMotion LAN
Average read- and write latencies at the storage adapter level were very close to the observed
latencies in Fluid Cache 2 msec
632 Monitoring user experience Figure 13 here shows the response time as experienced by each user as calculated by Login VSI The graph
clearly shows that the VSImax (Dynamic) value has not been reached and there were non-responsive or
inactive sessions This means that the array is capable of supporting the 1000 desktops and all users have
acceptable response times for applications that the user is has started
Figure 13 Login VSI user experience monitoring for 800 standard user desktops
30 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
633 Standard user test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SANndashbased VDI solution is able to host 800 virtual desktops and support
a standard user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only operations and
less than 2 percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to handle this login storm easily with low latency mdash it delivered the required 6500 IOPS with less
than 2 milliseconds of write latency with a 99 percent write VDI IO workload
64 Login storm and steady state with high IOPS (LoginVSI Medium +
Iometer) As mentioned earlier Iometer was used in desktop VMs alongside the Login VSI Medium workload to
simulate high IOPS type of VDI environment To mimic actual VDI workload profile the following Iometer
profile was used
20 KB block size 80 percent write 75 percent random with 25 msec burst delay
Figure 14 here shows the various IO characteristics during the login storm and steady state of these tests
Figure 14 IOPS and Cache Hit for the high IOPS test
On the Fluid Cache layer the maximum IOPS reached was approximately 72000 (or 90 IOPSVM) with
cache write-hit 100 percent and read-hit around 95 percent As shown in the Figure 15 the throughput
peaked at greater than 900 MBps with a peak latency of approximately 75 msec
31 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 15 Throughput and Latency for the high IOPS test
32 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
641 Server host performance Similar to the standard user test statistics for the vSphere hosts were captured by using VMware vCenter
Server during the high IOPS (heavy user) test also There are no significant differences in CPU disk space
and network utilization between standard users and heavy users The storage adapter latency is also
showing similar on hosts and observed on Fluid Cache
642 User experience monitoring Figure 16 here shows the response time as experienced by each user as calculated by Login VSI for the
heavy user test The graph shows that the VSImax (Dynamic) value was 796 indicating that the solution is
capable of supporting the 800 user high IOPS desktops with 90 IOPSVM
Figure 16 Login VSI user experience monitoring for 800 user high IOPS desktops
33 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
643 High IOPS (heavy user) test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SAN based VDI solution is able to host 800 virtual desktops and support a
high user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only and less than 2
percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to easily handle this login storm with low latency Subsequently it was able to handle 72000 IOPS
at high IOPS steady state with 90 IOPSVM with a maximum of 75 msec latency
34 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
7 Best practices This section provides the best practices derived from the testing and analysis in Section 6
71 Virtual Desktop Infrastructure This section provides best practices for the implementation of VDI using Dell Fluid Cache for SAN
711 Implement roaming profiles and folder redirection Dell recommends that all users in the VDI environment be configured with roaming profiles and folder
redirection This preserves user profiles and user data across boots while using non-persistent virtual
desktops
Also Dell recommends to use a high performance file service to provide the profile and folder redirection
A separate array may be used to host these volumes for best performance
712 Boot and login storm considerations Section 62 demonstrated the Fluid Cache for SAN performance under boot storm To avoid any potential
IO bursts because of boot storm and degraded user experience and performances Dell recommends that
all or portion of desktops be prebooted Connection brokers such as VMware Horizon View provide the
functionality to configure number of standby desktops
713 Windows 7 master image for desktop VMs Dell recommends that the operating system be customized in order to provide the best performance in a
VDI environment This includes disabling some services which may not be required This can improve
performance for the end user VMware has a specific set of recommendations and settings for Windows 7
and Windows 8 that allow for faster logins quicker screen refreshes and generally better performance
The VMware recommendations for Windows 7 and Windows 8 image optimization can be found here
httpwwwvmwarecomresourcestechresources10157
714 VDI Management infrastructure recommendations Dell recommends to have redundancy and load balancing for all VDI management services in the case of
VMware Horizon View solution as tested here the vSphere Server VMware Horizon View Servers and SQL
Servers Ideally these should be running on clustered hosts with VMware vSphere DRS (distributed
resource scheduler) and HA (high availability) enabled
72 Server host The vSphere servers hosting the infrastructure service providers and the virtual desktops are
recommended to be configured as follows
35 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Follow VMware and Dell best practices for installing and configuring vSphere
Separate virtual switches to segregate iSCSI SAN traffic VDI traffic vMotion traffic and Management
network traffic
Each network path must be assigned to a minimum of two physical NICs for high availability
VMware Knowledge Base article about best practices for installing vSphere 55
httpkbvmwarecomkb2052329
73 Network layer Dell recommends that at least two physical NICs on each vSphere server be dedicated to the VDI network
Use VLANs to segregate different types of network traffic on the same physical network In this case Dell
recommends to separate the infrastructure vMotion and VDI LAN traffic in to separate VLANs
Do not use VLANs to segregate iSCSI SAN and Fluide Cache traffic It is required that SAN and Cache traffic
be on separate dedicated physical network to provide the best performance
Virtual switches in vSphere have a default limit of 120 ports If the number of virtual desktops on each host
exceeds the available ports vSwitch properties should be changed to support the required number of
virtual desktops This change requires a restart of the host vSphere server
On iSCSI SAN switches Spanning tree must be disabled on switch ports connected to end devices for
server and storage ports The PortFast setting must be enabled in the switch configuration for these ports
Jumbo frames and Flow control (if the NICs support it) should be enabled for all components of the iSCSI
network
More information about configuring Dell Networking switches for use with Dell Storage iSCSI SANs is
available here
httpencommunitydellcomtechcenterstoragewwiki4250switch-configuration-guides-by-sisaspx
74 Storage The Dell SC storage arrays combined with Fluid Cache is an excellent platform for providing cost-effective
performance in VDI environments
Fluid Cache for SAN extends the power of Compellent intelligent data placement from the SAN to the
server By providing a single infrastructure for data at both high- and low ends of the performance
spectrum Fluid Cache for SAN with Storage Center 65 array software eliminates the tradeoffs between
server performance and full-featured SAN benefits such as reliability manageability and data protection
Dell recommends to have separate volumes for base image and virtual desktops This enables better
manageability of the volumes easier performance monitoring and allows easy future growth
Dell recommends to use a separate high performance file service to provide file shares for roaming
profiles and user shares
36 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
8 Conclusion The technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed by using a Horizon View VDI platform leveraging Dell Fluid Cache for SAN The storage IO
characteristics under various VDI workload scenarios (boot storm login storm and steady state) along
with performance characteristics throughout the VDI stack (for example vSphere server performance and
user experience) demonstrate the optimal configuration of the infrastructure used for this VDI
deployment For more information about Fluid Cache contact your Dell account manager
37 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
A Horizon view solution configuration
Table 7 Hardware components
Hardware components Description
Virtual Desktops 4 timesDell PowerEdge R720 Servers (Fluid Cache Providers)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
2times350 GB Dell Express Flash PCIe SSDs
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
4 x Dell PowerEdge R720 Servers (Fluid Cache Clients)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55 U2 on all R720 servers Windows 7 (64 Bit) VMs
Infrastructure Servers 2 x Dell PowerEdge R720 servers
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
96 GB RAM
2times300 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55U2 on all R720 servers VMs are loaded with Microsoft Windows 2008 R2
Active Directory
VMware Horizon View 60 Server 1
VMware Horizon View 60 Server 2
VMware vCenter Server 55 update 2
VMware Horizon View Composer
SQL Server
File Server
Login VSI Launchers 8 x Dell PowerEdge M610 servers
2timesIntelreg Xeonreg E-5503 200 GHz Processors
16 GB RAM
4times146 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57711 10GbE NIC
ESXi 51 installed on all R810 servers VMs are loaded with Microsoft Windows 7 64bit Each VM supports up to 30 Login VSI launcher sessions
38 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Network Management VDI LAN
1timesDell Force10 S55 1Gb Ethernet Switch
iSCSI SAN
1timesDell Force10 S4810 10Gb Ethernet Switch
Cache network
1timesDell Force10 S4810 10Gb Ethernet Switch
One Force10 S4810 switch might suffice for all the cache iSCSI SAN VDI LAN and management traffic
Storage 2timesDell Compellent SC8000 controllers 4times6Gb SAS 4-port PCI-E Full-height cards for back-end connectivity 2times10Gb iSCSI 2 port PCI-E Low-profile IO cards for front end connectivity 1timesDell Compellent SC200 disk enclosures 12times4TB NL-SAS 6Gb 72K 35rdquo drives
User Data Infrastructure VMs Virtual Desktops
Performance Monitoring
Dell Compellent Enterprise Manager Dell Fluid Cache for SAN performance monitoring tool () vCenter Performance monitoring Liquidware Stratusphere UX
Performance monitoring on Compellent arrays Fluid Cache performance monitoring Performance monitoring and capture at the ESXi host User experience monitoring on the virtual desktop
39 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 8 Software components
Software components Description Version
Dell Fluid Cache for SAN 20
Dell Compellent Storage Center 64
Dell Compellent Enterprise Manager 64
VMware Horizon View Server 60
VMware Horizon View Composer 60
VMware Horizon View Agent 60
VMware Horizon View Client 64-bit 60
VMware ESXi Hypervisor 55 U2
VMware vCenter Server 55 U2
Microsoft SQL Server 2008R2 Enterprise x64 105016001
Client VM OS Microsoft Windows 7 Enterprise x64 SP1
Management VM OS Microsoft Windows Server 2008 Enterprise R2 x64 SP1
Microsoft Office MS office 2010 Standard Service Pack 1
Login VSI Version 40
Iometer 20060727
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
11 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
313 Horizon view desktop pools A desktop pool is a term VMware uses to describe a collection of desktops that are managed as a single
entity by the Horizon View Administrator interface Horizon View desktop pools allow administrators to
group users depending on the type of service the user requires There are two types of pools ndash Automated
and Manual
In Horizon View an Automated Pool is a collection of VMs cloned from a base template while a Manual
pool is created by the Horizon View Manager from existing desktop sources physical or virtual For each
desktop in the Manual pool the administrator selects a desktop source to deliver Horizon View access to
the clients
VMware View Personas profile management features can be used to achieve persistent desktop-like
behavior on non-persistent desktops By using these features an administrator can design a user account
where the configuration settings are written to a remote profile that is stored separately from the virtual
desktop image files This reduces the need for additional management on individual virtual desktops while
still providing a customized user experience
314 Using linked clones Significant storage space savings and increased efficiencies in desktop VM provisioning and administration
are possible when using VMware-linked clones A linked clone is a duplicate VM that shares the same base
image with the original VM but has separate differential data disks to track the differences from the
original one Each linked clone functions as an independent desktop VM with its own unique identity
Because linked clones share the same base image they consume significantly less storage disk space than
a set of completely independent VM images Temporary system data and other data unique to each linked
clone desktop VM are written to separate differential data storage and these temporary changes are
discarded during restart andor user logoff Persistent data such as user profiles applications and user
data can be optionally redirected to a CIFS share With this model software maintenance updates
antivirus remediation and patches need to be applied only on the base image These base image changes
automatically take effect on all linked clones without affecting any user settings and data
To configure linked clones the administrator creates a snapshot of a parent VM image with the required
OS settings and software installed Horizon View Composer first creates a full replica (clone) of the parent
VM and then uses this replica to create linked clones The replica can be placed on the same data store as
the linked clones or on a separate data store
More information about configuring linked clones can be found in the ldquoCreating Desktop Poolsrdquo section of
the VMware Horizon View Online Library here
315 Hypervisor platform VMware vSphere 55 VMware vSphere 55 is the enterprise virtualization platform used for building VDI and cloud
infrastructures VMware vSphere 55 includes three major layers virtualization management and interface
The virtualization layer includes infrastructure and application services The management layer is central
12 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
for configuring provisioning and managing virtualized environments The interface layer includes the
vSphere client and the vSphere web client
Throughout the solution all VMware and Microsoft best practices and prerequisites for core services were
used (NTP DNS Active Directory and others)
32 Hardware Dell infrastructure Figure 3 shows the design of the infrastructure for the Horizon Viewndashbased high IOPS type VDI
deployment that leverages Fluid Cache
An eight-node vSphere server cluster is used to host the virtual desktops Each of these server nodes has a
direct-attached PCIe SSD that is added to the Fluid Cache pool thus making each server a Fluid Cache
Provider (a server contributing to the Fluid Cache capacity) The eight PCIe SSDs were distributed among
all the servers to better balance the load on the Fluid Cache server Fluid Cache server1 These servers
were connected by using a private caching network to provide the Fluid Cache functionality Also the
servers were connected through a separate managementVDI client network and a 10 GB Ethernet iSCSI
SAN network
Another two-node vSphere server cluster is used to host the VDI infrastructure VMs such as vCenter
server View Connection server View Composer server SQL Server and Active Directory etc These
infrastructure servers were connected to the management network and the iSCSI SAN network
The Compellent storage array for the solution has two controllers and a mix of Write Intensive (WI) SSDs
15K SAS HDDs and 72K NL-SAS HDDs to provide the optimal performance and capacity needed for the
solution
Two switches are stacked together for different networks to provide redundancy in the networking layer
Ideally 40 GB Ethernet switches are recommended for the cache network While 1 GB Ethernet switches
can be used for management network it is better to use 10 GB Ethernet switches combining management
and VDI client networks The same 10 GB Ethernet switches can be used for iSCSI SAN also (with different
network traffic segmented by VLANs) provided they have adequate bandwidth needed for the specific VDI
deployment
Information about how this reference architecture was developed ensuring the optimal utilization across
the servers switches and storage arrays is discussed later in the following sections of this technical white
paper
1 Fluid Cache does not require all servers to be a Fluid Cache Provider For example in this case four
servers could have two PCIe SSDs each This configuration with four Fluid Cache Provider and four Fluid Cache Client would have had same capacity for Fluid Cache pool and all eight servers could have taken advantage of Fluid Cache However the chosen configuration for the technical white paper provides better performance the because VDI application caching load is unforming distributed among all the available servers
13 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 3 Infrastructure Set-up for VDI Solution
1 Enterprise Manager Console 2 Management and VDI Client Network 3 vSphere Servers hosting virtual desktops 4 Cache network switches (2)
5 SAN switch 6 Storage Center controllers (2) 7 Storage Center expansion enclosures (2) 8 Server hosting VDI infrastructure VMs
(Server 1) (Server 2)
14 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
4 Solution configuration This section provides information about the solution configuration and test setup for hosting Horizon View
virtual desktops including infrastructure components networking and storage subsystems
41 Host design considerations The entire VDI solution was installed in two vSphere server clusters The clusters included
Figure 4 vSphere server clusters
Infrastructure Cluster Two Dell PowerEdge R720 servers hosting VMs for Active Directory
services VMware vCenter 55 server Horizon View Connection server (primary and secondary)
View Composer server Microsoft Windows Server 2012 R2 based file server and SQL Server 2012
R2
View Client Cluster Eight Dell PowerEdge R720 servers hosting the virtual desktops Each server
had
o 2times10 core Intel Xeon CPU E5-2690v2 300GHz
o 256 GB RAM
o 1times350 GB Dell Express Flash PCIe SSD
o 1timesMellanox Connect ndash X3 card
o 1timesDual-port Broadcom NetXtreme II BCM57810 10 Gigabit NIC
o 1timesQuad-port Broadcom NetXtreme BCM5720 Gigabit NIC
Along with the other servers the above servers 40 LoginVSI launcher VMs were used to generate VDI
workload They can be hosted by two PowerEdge R720 servers or equivalent for VDI load generation
purposes
15 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
42 Network design considerations Figure 5 here shows the network layout of one of the eight PowerEdge R720 servers with vSphere 55
installed
Figure 5 vSphere host network configuration
Three network switches are used in the Fluid Cache for VDI implementation One Force10 S55 1 GB switch
for all management traffic and VDI traffic The management traffic includes hosts and vSphere
management Compellent storage management and so on The networks are segregated by using VLANs
to separate different types of traffic
One Dell Force10 S4810 10 GB switch is used for Fluid Cache cache network which supports all the traffic
between cache layer on eight VDI VM hosts Another Force10 S4810 10 GB switch is used for iSCSI
network between infrastructure hosts VDI VM hosts and Compellent SC8000
Appendix B has extended information on the vSwitch configuration for each vSphere host
16 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
43 Dell Compellent SC8000 storage array configurations The storage used to host the virtual desktops was a Dell Compellent SC8000 array running Storage Center
Operating System (SCOS) 65 All two front-end ports were 10 GB iSCSI and all two back-end ports were
six GB serial-attached SCSI (SAS) The array used two external enclosures with Write Intensive (WI) SSDs
comprising Tier 1 and 15K SAS HDDs comprising Tier 2 for performance Also 72 NL-SAS drives were
used in Tier 3 to provide capacity for user data Table 2 summarizes the storage hardware configuration
Table 2 Storage hardware components
Storage role Type Qty Description
Controllers SC8000 2 System Center Operating System (SCOS) 65
Enclosures External 2 24 bay ndash 25rdquo disk drive enclosure
Ports Ethernet ndash 10 Gbps 2 Front end host connectivity
SAS - 6 Gbps 4 Back end drive connectivity
Drives 400 GB WI SSD 12 11 active with 1 hot spare
300 GB 15K SAS HDD
21 20 active with 1 hot spare
4 TB 72K NL-SAS HDD
12 11 active with 1 hot spare
The volumes created to host the virtual desktops took advantage of the Compellent Dynamic Capacity
technology for efficient capacity allocation Table 3 lists the volume layout used for the infrastructure
functions including user data
Table 3 Volume layout for hosting infrastructure components and user data
Volume name Size Purpose
Infrastructure 500 GB Storage for Active Directory SQL Server vCenter Server View Connection Server View Composer and File Server
UserSpace 2 TB Storage for User profiles and folder redirection space (Average 25 GB per user)
Along with the infrastructure volumes the storage array also provided shared storage for hosting the
virtual desktops The volume layout used for configuring the base image (View Composer Replica) and VDI
volumes on the array is shown in Table 4
17 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 4 Dell Storage PS4210XS layout for volumes hosting virtual desktops
Volume name Size Purpose
View-Replicas1 and 2 100 GB each Storage for base image for VDI deployment
VDI-Images1 through 8 500 GB each Storage for VDI VMs in VDI Cluster Each volume hosted 100 desktops
44 vSphere host network configuration VMware vSphere 55 hypervisor was installed on all servers The network configuration on each of those
hosts is described here Each vSphere host was configured with five virtual switches vSwitch0 vSwitch1
vSwitch2 vSwitch3 and vSwitch4 to separate different types of traffic on the system
Table 5 vSwitch configuration in vSphere hosts
vSwitch Description
vSwitch0 Management Network
vSwitch1 and vSwitch2 iSCSI SAN
vSwitch3 Fluid Cache VLAN
vSwitch4 VDI LAN
For additional information about individual vSwitch configuration refer to Appendix B in the Dell technical
white paper
45 Horizon view configuration Horizon View 60 was installed by using the documentation provided by VMware
Horizon View 601 installation documentation
httpswwwvmwarecomsupportpubsview_pubshtml
Table 6 Specific configuration used in the tests
Purpose Count Type Memory CPU
Horizon View Connection Servers
2 VM 16 GB 8nos
View Composer Server 1 VM 8 GB 8nos
18 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
46 Windows 7 VM configuration Following the guidelines from VMware and Login VSI the Windows 7 base image was generated based on
a generic base VM with the following properties
VMware Virtual Hardware version 8
Two virtual CPU
3 GB RAM with 15GB reserved
25 GB virtual hard drive
One virtual NIC connected to the VDI network
Windows 7 64-bit OS
Also the base image was customized by using the VMware Horizon with View Optimization Guide for
Windows 7 and Windows 8 available at this location httpwwwvmwarecomfilespdfVMware-View-
OptimizationGuideWindows7-ENpdf
19 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
5 Horizon view test methodology This section outlines the test objectives along with the test tools and criteria used to determine the
optimal virtual desktop density and best practices for deploying Horizon View on Dell Fluid Cache for SAN
for high IOPS type VDI environment
51 Test objectives As noted in Section 11 the test objectives were
Develop an optimal end-to-end infrastructure design for a Horizon View and vSpherendashbased high
user type of VDI solution deployed by using the Fluid Cache Compellent storage PowerEdge
servers and Dell Networking switches
Determine the performance at every layer of the VDI solution stack under high IOPS workload For
example desktops generating 80ndash90 IOPSVM at steady state
Determine the performance impact of peak IO activity such as boot and login storms
52 Test tools All tests were conducted by using Login VSI 40 as the workload generator and user experience analyzer
tool Login VSI is a benchmarking tool to measure the performance and scalability of centralized desktop
environments such as Server Based Computing (SBC) and VDI
Note More information can be found at the Login VSI website httpwwwloginvsicom
In addition to Login VSI Iometer is used in desktop VMs to simulate high IOPS conditions Iometer is
invoked in desktop VMs by using custom scripting of Login VSI workloads
Note More information can be found at the Iometer project website httpwwwiometerorg
521 Load generation First the ldquoMediumrdquo workload from Login VSI was used to simulate the standard user workload The
characteristics of the Medium workload are
Up to five applications are started simultaneously
Applications include Microsoft Internet Explorer Microsoft Word Microsoft Excel Microsoft
PowerPoint PDF reader 7-Zip compression software Movie player and FreeMind
After a session is started the medium workload repeats approximately after every 48 minutes
During a loop the response time is measured after every 3ndash4 minutes
Idle time is about two minutes in each 48-minute loop
Type rate is approximately 160 milliseconds per character
After the test by using Login VSI Medium was complete tests were rerun with Login VSI Medium and
Iometer in desktop VMs to simulate high IOPS VDI workload While the Login VSI Medium generates 8ndash10
20 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
IOPSVM the latter method was able to generate 80ndash90 IOPSVM For these tests each VM in the Horizon
view pool is created with standard LoginVSI contents and applications Also Iometer is installed on each
VM After the user logs in a customized logon script starts the Iometer with required IO specification (icf
file)
522 Monitoring tools The following monitoring tools were used
Dell Compellent Enterprise Manager for monitoring Fluid Cache and Compellent SC8000 storage
array performance
VMware vCenter statistics for vSphere performance
Login VSI Analyzer for end user performance statistics
Detailed performance metrics were captured from the storage arrays hypervisors virtual desktops and
the load generators during the tests
53 Test criteria The primary focus of the tests is to validate the 800 desktop high IOPS type of VDI architecture with
acceptable user experience by using Fluid Cache for SAN VDI configurations involve many components at
different layers ndash application hypervisor server network and storage As a result multiple metrics need to
be captured at different layers to ensure that the environment is healthy and performing optimally and
appropriately for all users
The specific test criteria are described in the following sections
531 Storage capacity and IO latency The typical industry standard latency limit for storage disk IO is 10 milliseconds Maintaining this limit
ensures good user application response times when there are no other bottlenecks at the infrastructure
layer In addition Dell recommends to maintain a 10 percent spare disk space on the storage array for
optimal performance
532 System utilization at the hypervisor Even though the primary focus of these tests was storage characterization additional metrics at the
hypervisor infrastructure layer were defined to ensure solution consistency These were
CPU utilization on any vSphere server must not exceed 85 percent
Minimal memory ballooning on the VMs
Total network bandwidth utilization must not exceed 90 percent on any one link
TCPIP storage network retransmissions should be less than 05 percent
21 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
533 Virtual desktop user experience Login VSI Analyzer was also used to gather metrics on the user experience at the virtual desktop layer to
ensure that all the desktops had acceptable levels of application performance Login VSI uses the VSImax
parameter to determine the maximum number of sessions that can be obtained from a deployed solution
The calculation methodology used in VSImax is available here
httpwwwloginvsicomdocumentationindexphptitle=Analyzing_Results
534 Test configuration A single virtual desktop pool was configured by using the VMware Horizon View Administrator interface
Each pool was built from a Windows 7 base image The Windows 7 configuration information is available
in Section 46
Desktop pool properties
Automatic Desktop Pool
Users are assigned using Floating assignments
View Storage Accelerator is enabled for all hosts with a refresh period of seven days
800 desktops were deployed across eight hosts (100 desktops a host)
Replica images were stored on a separate volume
22 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
6 Test results and analysis This section presents the results from the different Horizon View VDI characterization tests and the key
findings from each test The testing was focused on the high IOPS workload profile
61 Test scenarios The following tests were conducted to gather results and analysis on the solution stack
1 Boot storm Boot storms represent the worst-case scenario where many virtual desktops are
turned on at the same time and they all contend for the system resources simultaneously This test
was used to evaluate if the storage array hosting the desktops was capable of handling huge
variation in storage IO without causing significant impact on other services
2 Login storm Login storms also represent a high IOPS situation where many users are logging in to
their virtual desktops at the beginning of a workday or a shift In this test all the desktops were
pre-booted and left in an idle state for more than 20 minutes to let their IO settle before running
the Login VSI Medium workload to simulate users logging in to their virtual desktops
3 Steady state workload for standard users with normal IOPS After the login storm for the previous
test was completed the Login VSI Medium workload was allowed to run for at least one hour to
simulate the real-world scenario of users performing their daily tasks The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
4 Steady state workload for users with high IOPS The previous test was repeated with the Login
VSI Medium workload and Iometer scripts in desktop VMs as described in Section 521 to simulate
real-world heavy users performing their daily tasks with high IOPS The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
The following sections provide results from the boot storm login storm and steady state testing for the
Fluid Cache for SAN based VDI solution
23 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
62 Boot storm IO To simulate a boot storm the virtual desktops were reset simultaneously from the VMware vSphere client
Figure 6 shows the IO pattern on the Fluid Cache for the boot storm
Figure 6 SAN HQ data showing boot storm performance with Fluid Cache array
With 800 desktops the boot storm generated about 115000 total IOPS with a majority of them being
write operations All desktops were available for use in less than four minutes
24 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
63 Login storm and steady state for standard users (LoginVSI
Medium) Login VSI was programmed to start 800 virtual desktops over a period of about 60 minutes after pre-
booting the virtual desktops The peak IOPS during the login storm observed by the vSphere servers
hosting the desktops was about 6500 IOPS (8ndash10 IOPS a VM)
In a standard user environment login storms generate significantly more write IOPS than a boot storm or
steady state because of multiple factors such as
User profile activity
Starting operating system services on the desktop
First start of applications
After a virtual desktop has achieved a steady state after user login the Windows 7 OS has cached
applications in memory and does not need to access storage each time the application is started This
leads to lesser IOPS during the steady state Figure 7 here shows the various IO characteristics during the
login storm and steady state of these tests
25 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 7 IOPS and Cache Hit for the standard user test
On the Fluid Cache layer the maximum IOPS reached 6500 with cache-hit reaching 100 percent and
read-hit around 95 percent As shown in the Figure 8 here the throughput peaked at 98 MBps with a low
latency of less than 2 msec
26 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 8 Throughput and Latency for the standard user test
631 Server host performance During the login storm and steady state of the test the vSphere host CPU memory network and storage
performance were measured on all the servers that hosted the virtual desktops The performance of one
such vSphere server is given here The other vSphere servers had similar performance characteristics
Statistics for the vSphere hosts were captured by using VMware vCenter Server The figures here show the
CPU memory and network utilization for boot storm login storm and steady state of one of the vSphere
servers hosting the virtual desktops The results shown here are for a test run with 800 no standard user
desktops in the desktop pool
27 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 9 Average CPU performance per core on one vSphere host during login storm and steady state
Figure 10 Disk space usage during login storm and steady state
0
10
20
30
40
50
60
70
80
90
100
1020 1045 1110 1135 1200 1225
Per
cen
t
Time
CPU Performance
0
50
100
150
200
250
300
1020 1040 1100 1120 1140 1200 1220
GB
Time
Memory Performance
Granted Swap used Shared common
28 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 11 Overall network performance during login storm and steady state
Figure 12 Storage adapter performance during login storm and steady state
0
10000
20000
30000
40000
50000
60000
70000
1020 1045 1110 1135 1200 1225
kBp
s
Time
Network Performance
0
05
1
15
2
25
1020 1045 1110 1135 1200 1225
mSe
c
Time
Storage adaptor performance
29 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
The key observations from the statistics were
CPU utilization was less than the 85 percent threshold throughout the test
Active disk space usage was about 80 percent during the boost storm and about 60 percent
during login storm and steady state There was minimal-or no memory ballooning observed
Network utilization was about 45 percent which included all the networks such as iSCSI SAN VDI
LAN Management LAN and vMotion LAN
Average read- and write latencies at the storage adapter level were very close to the observed
latencies in Fluid Cache 2 msec
632 Monitoring user experience Figure 13 here shows the response time as experienced by each user as calculated by Login VSI The graph
clearly shows that the VSImax (Dynamic) value has not been reached and there were non-responsive or
inactive sessions This means that the array is capable of supporting the 1000 desktops and all users have
acceptable response times for applications that the user is has started
Figure 13 Login VSI user experience monitoring for 800 standard user desktops
30 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
633 Standard user test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SANndashbased VDI solution is able to host 800 virtual desktops and support
a standard user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only operations and
less than 2 percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to handle this login storm easily with low latency mdash it delivered the required 6500 IOPS with less
than 2 milliseconds of write latency with a 99 percent write VDI IO workload
64 Login storm and steady state with high IOPS (LoginVSI Medium +
Iometer) As mentioned earlier Iometer was used in desktop VMs alongside the Login VSI Medium workload to
simulate high IOPS type of VDI environment To mimic actual VDI workload profile the following Iometer
profile was used
20 KB block size 80 percent write 75 percent random with 25 msec burst delay
Figure 14 here shows the various IO characteristics during the login storm and steady state of these tests
Figure 14 IOPS and Cache Hit for the high IOPS test
On the Fluid Cache layer the maximum IOPS reached was approximately 72000 (or 90 IOPSVM) with
cache write-hit 100 percent and read-hit around 95 percent As shown in the Figure 15 the throughput
peaked at greater than 900 MBps with a peak latency of approximately 75 msec
31 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 15 Throughput and Latency for the high IOPS test
32 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
641 Server host performance Similar to the standard user test statistics for the vSphere hosts were captured by using VMware vCenter
Server during the high IOPS (heavy user) test also There are no significant differences in CPU disk space
and network utilization between standard users and heavy users The storage adapter latency is also
showing similar on hosts and observed on Fluid Cache
642 User experience monitoring Figure 16 here shows the response time as experienced by each user as calculated by Login VSI for the
heavy user test The graph shows that the VSImax (Dynamic) value was 796 indicating that the solution is
capable of supporting the 800 user high IOPS desktops with 90 IOPSVM
Figure 16 Login VSI user experience monitoring for 800 user high IOPS desktops
33 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
643 High IOPS (heavy user) test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SAN based VDI solution is able to host 800 virtual desktops and support a
high user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only and less than 2
percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to easily handle this login storm with low latency Subsequently it was able to handle 72000 IOPS
at high IOPS steady state with 90 IOPSVM with a maximum of 75 msec latency
34 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
7 Best practices This section provides the best practices derived from the testing and analysis in Section 6
71 Virtual Desktop Infrastructure This section provides best practices for the implementation of VDI using Dell Fluid Cache for SAN
711 Implement roaming profiles and folder redirection Dell recommends that all users in the VDI environment be configured with roaming profiles and folder
redirection This preserves user profiles and user data across boots while using non-persistent virtual
desktops
Also Dell recommends to use a high performance file service to provide the profile and folder redirection
A separate array may be used to host these volumes for best performance
712 Boot and login storm considerations Section 62 demonstrated the Fluid Cache for SAN performance under boot storm To avoid any potential
IO bursts because of boot storm and degraded user experience and performances Dell recommends that
all or portion of desktops be prebooted Connection brokers such as VMware Horizon View provide the
functionality to configure number of standby desktops
713 Windows 7 master image for desktop VMs Dell recommends that the operating system be customized in order to provide the best performance in a
VDI environment This includes disabling some services which may not be required This can improve
performance for the end user VMware has a specific set of recommendations and settings for Windows 7
and Windows 8 that allow for faster logins quicker screen refreshes and generally better performance
The VMware recommendations for Windows 7 and Windows 8 image optimization can be found here
httpwwwvmwarecomresourcestechresources10157
714 VDI Management infrastructure recommendations Dell recommends to have redundancy and load balancing for all VDI management services in the case of
VMware Horizon View solution as tested here the vSphere Server VMware Horizon View Servers and SQL
Servers Ideally these should be running on clustered hosts with VMware vSphere DRS (distributed
resource scheduler) and HA (high availability) enabled
72 Server host The vSphere servers hosting the infrastructure service providers and the virtual desktops are
recommended to be configured as follows
35 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Follow VMware and Dell best practices for installing and configuring vSphere
Separate virtual switches to segregate iSCSI SAN traffic VDI traffic vMotion traffic and Management
network traffic
Each network path must be assigned to a minimum of two physical NICs for high availability
VMware Knowledge Base article about best practices for installing vSphere 55
httpkbvmwarecomkb2052329
73 Network layer Dell recommends that at least two physical NICs on each vSphere server be dedicated to the VDI network
Use VLANs to segregate different types of network traffic on the same physical network In this case Dell
recommends to separate the infrastructure vMotion and VDI LAN traffic in to separate VLANs
Do not use VLANs to segregate iSCSI SAN and Fluide Cache traffic It is required that SAN and Cache traffic
be on separate dedicated physical network to provide the best performance
Virtual switches in vSphere have a default limit of 120 ports If the number of virtual desktops on each host
exceeds the available ports vSwitch properties should be changed to support the required number of
virtual desktops This change requires a restart of the host vSphere server
On iSCSI SAN switches Spanning tree must be disabled on switch ports connected to end devices for
server and storage ports The PortFast setting must be enabled in the switch configuration for these ports
Jumbo frames and Flow control (if the NICs support it) should be enabled for all components of the iSCSI
network
More information about configuring Dell Networking switches for use with Dell Storage iSCSI SANs is
available here
httpencommunitydellcomtechcenterstoragewwiki4250switch-configuration-guides-by-sisaspx
74 Storage The Dell SC storage arrays combined with Fluid Cache is an excellent platform for providing cost-effective
performance in VDI environments
Fluid Cache for SAN extends the power of Compellent intelligent data placement from the SAN to the
server By providing a single infrastructure for data at both high- and low ends of the performance
spectrum Fluid Cache for SAN with Storage Center 65 array software eliminates the tradeoffs between
server performance and full-featured SAN benefits such as reliability manageability and data protection
Dell recommends to have separate volumes for base image and virtual desktops This enables better
manageability of the volumes easier performance monitoring and allows easy future growth
Dell recommends to use a separate high performance file service to provide file shares for roaming
profiles and user shares
36 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
8 Conclusion The technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed by using a Horizon View VDI platform leveraging Dell Fluid Cache for SAN The storage IO
characteristics under various VDI workload scenarios (boot storm login storm and steady state) along
with performance characteristics throughout the VDI stack (for example vSphere server performance and
user experience) demonstrate the optimal configuration of the infrastructure used for this VDI
deployment For more information about Fluid Cache contact your Dell account manager
37 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
A Horizon view solution configuration
Table 7 Hardware components
Hardware components Description
Virtual Desktops 4 timesDell PowerEdge R720 Servers (Fluid Cache Providers)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
2times350 GB Dell Express Flash PCIe SSDs
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
4 x Dell PowerEdge R720 Servers (Fluid Cache Clients)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55 U2 on all R720 servers Windows 7 (64 Bit) VMs
Infrastructure Servers 2 x Dell PowerEdge R720 servers
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
96 GB RAM
2times300 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55U2 on all R720 servers VMs are loaded with Microsoft Windows 2008 R2
Active Directory
VMware Horizon View 60 Server 1
VMware Horizon View 60 Server 2
VMware vCenter Server 55 update 2
VMware Horizon View Composer
SQL Server
File Server
Login VSI Launchers 8 x Dell PowerEdge M610 servers
2timesIntelreg Xeonreg E-5503 200 GHz Processors
16 GB RAM
4times146 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57711 10GbE NIC
ESXi 51 installed on all R810 servers VMs are loaded with Microsoft Windows 7 64bit Each VM supports up to 30 Login VSI launcher sessions
38 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Network Management VDI LAN
1timesDell Force10 S55 1Gb Ethernet Switch
iSCSI SAN
1timesDell Force10 S4810 10Gb Ethernet Switch
Cache network
1timesDell Force10 S4810 10Gb Ethernet Switch
One Force10 S4810 switch might suffice for all the cache iSCSI SAN VDI LAN and management traffic
Storage 2timesDell Compellent SC8000 controllers 4times6Gb SAS 4-port PCI-E Full-height cards for back-end connectivity 2times10Gb iSCSI 2 port PCI-E Low-profile IO cards for front end connectivity 1timesDell Compellent SC200 disk enclosures 12times4TB NL-SAS 6Gb 72K 35rdquo drives
User Data Infrastructure VMs Virtual Desktops
Performance Monitoring
Dell Compellent Enterprise Manager Dell Fluid Cache for SAN performance monitoring tool () vCenter Performance monitoring Liquidware Stratusphere UX
Performance monitoring on Compellent arrays Fluid Cache performance monitoring Performance monitoring and capture at the ESXi host User experience monitoring on the virtual desktop
39 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 8 Software components
Software components Description Version
Dell Fluid Cache for SAN 20
Dell Compellent Storage Center 64
Dell Compellent Enterprise Manager 64
VMware Horizon View Server 60
VMware Horizon View Composer 60
VMware Horizon View Agent 60
VMware Horizon View Client 64-bit 60
VMware ESXi Hypervisor 55 U2
VMware vCenter Server 55 U2
Microsoft SQL Server 2008R2 Enterprise x64 105016001
Client VM OS Microsoft Windows 7 Enterprise x64 SP1
Management VM OS Microsoft Windows Server 2008 Enterprise R2 x64 SP1
Microsoft Office MS office 2010 Standard Service Pack 1
Login VSI Version 40
Iometer 20060727
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
12 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
for configuring provisioning and managing virtualized environments The interface layer includes the
vSphere client and the vSphere web client
Throughout the solution all VMware and Microsoft best practices and prerequisites for core services were
used (NTP DNS Active Directory and others)
32 Hardware Dell infrastructure Figure 3 shows the design of the infrastructure for the Horizon Viewndashbased high IOPS type VDI
deployment that leverages Fluid Cache
An eight-node vSphere server cluster is used to host the virtual desktops Each of these server nodes has a
direct-attached PCIe SSD that is added to the Fluid Cache pool thus making each server a Fluid Cache
Provider (a server contributing to the Fluid Cache capacity) The eight PCIe SSDs were distributed among
all the servers to better balance the load on the Fluid Cache server Fluid Cache server1 These servers
were connected by using a private caching network to provide the Fluid Cache functionality Also the
servers were connected through a separate managementVDI client network and a 10 GB Ethernet iSCSI
SAN network
Another two-node vSphere server cluster is used to host the VDI infrastructure VMs such as vCenter
server View Connection server View Composer server SQL Server and Active Directory etc These
infrastructure servers were connected to the management network and the iSCSI SAN network
The Compellent storage array for the solution has two controllers and a mix of Write Intensive (WI) SSDs
15K SAS HDDs and 72K NL-SAS HDDs to provide the optimal performance and capacity needed for the
solution
Two switches are stacked together for different networks to provide redundancy in the networking layer
Ideally 40 GB Ethernet switches are recommended for the cache network While 1 GB Ethernet switches
can be used for management network it is better to use 10 GB Ethernet switches combining management
and VDI client networks The same 10 GB Ethernet switches can be used for iSCSI SAN also (with different
network traffic segmented by VLANs) provided they have adequate bandwidth needed for the specific VDI
deployment
Information about how this reference architecture was developed ensuring the optimal utilization across
the servers switches and storage arrays is discussed later in the following sections of this technical white
paper
1 Fluid Cache does not require all servers to be a Fluid Cache Provider For example in this case four
servers could have two PCIe SSDs each This configuration with four Fluid Cache Provider and four Fluid Cache Client would have had same capacity for Fluid Cache pool and all eight servers could have taken advantage of Fluid Cache However the chosen configuration for the technical white paper provides better performance the because VDI application caching load is unforming distributed among all the available servers
13 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 3 Infrastructure Set-up for VDI Solution
1 Enterprise Manager Console 2 Management and VDI Client Network 3 vSphere Servers hosting virtual desktops 4 Cache network switches (2)
5 SAN switch 6 Storage Center controllers (2) 7 Storage Center expansion enclosures (2) 8 Server hosting VDI infrastructure VMs
(Server 1) (Server 2)
14 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
4 Solution configuration This section provides information about the solution configuration and test setup for hosting Horizon View
virtual desktops including infrastructure components networking and storage subsystems
41 Host design considerations The entire VDI solution was installed in two vSphere server clusters The clusters included
Figure 4 vSphere server clusters
Infrastructure Cluster Two Dell PowerEdge R720 servers hosting VMs for Active Directory
services VMware vCenter 55 server Horizon View Connection server (primary and secondary)
View Composer server Microsoft Windows Server 2012 R2 based file server and SQL Server 2012
R2
View Client Cluster Eight Dell PowerEdge R720 servers hosting the virtual desktops Each server
had
o 2times10 core Intel Xeon CPU E5-2690v2 300GHz
o 256 GB RAM
o 1times350 GB Dell Express Flash PCIe SSD
o 1timesMellanox Connect ndash X3 card
o 1timesDual-port Broadcom NetXtreme II BCM57810 10 Gigabit NIC
o 1timesQuad-port Broadcom NetXtreme BCM5720 Gigabit NIC
Along with the other servers the above servers 40 LoginVSI launcher VMs were used to generate VDI
workload They can be hosted by two PowerEdge R720 servers or equivalent for VDI load generation
purposes
15 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
42 Network design considerations Figure 5 here shows the network layout of one of the eight PowerEdge R720 servers with vSphere 55
installed
Figure 5 vSphere host network configuration
Three network switches are used in the Fluid Cache for VDI implementation One Force10 S55 1 GB switch
for all management traffic and VDI traffic The management traffic includes hosts and vSphere
management Compellent storage management and so on The networks are segregated by using VLANs
to separate different types of traffic
One Dell Force10 S4810 10 GB switch is used for Fluid Cache cache network which supports all the traffic
between cache layer on eight VDI VM hosts Another Force10 S4810 10 GB switch is used for iSCSI
network between infrastructure hosts VDI VM hosts and Compellent SC8000
Appendix B has extended information on the vSwitch configuration for each vSphere host
16 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
43 Dell Compellent SC8000 storage array configurations The storage used to host the virtual desktops was a Dell Compellent SC8000 array running Storage Center
Operating System (SCOS) 65 All two front-end ports were 10 GB iSCSI and all two back-end ports were
six GB serial-attached SCSI (SAS) The array used two external enclosures with Write Intensive (WI) SSDs
comprising Tier 1 and 15K SAS HDDs comprising Tier 2 for performance Also 72 NL-SAS drives were
used in Tier 3 to provide capacity for user data Table 2 summarizes the storage hardware configuration
Table 2 Storage hardware components
Storage role Type Qty Description
Controllers SC8000 2 System Center Operating System (SCOS) 65
Enclosures External 2 24 bay ndash 25rdquo disk drive enclosure
Ports Ethernet ndash 10 Gbps 2 Front end host connectivity
SAS - 6 Gbps 4 Back end drive connectivity
Drives 400 GB WI SSD 12 11 active with 1 hot spare
300 GB 15K SAS HDD
21 20 active with 1 hot spare
4 TB 72K NL-SAS HDD
12 11 active with 1 hot spare
The volumes created to host the virtual desktops took advantage of the Compellent Dynamic Capacity
technology for efficient capacity allocation Table 3 lists the volume layout used for the infrastructure
functions including user data
Table 3 Volume layout for hosting infrastructure components and user data
Volume name Size Purpose
Infrastructure 500 GB Storage for Active Directory SQL Server vCenter Server View Connection Server View Composer and File Server
UserSpace 2 TB Storage for User profiles and folder redirection space (Average 25 GB per user)
Along with the infrastructure volumes the storage array also provided shared storage for hosting the
virtual desktops The volume layout used for configuring the base image (View Composer Replica) and VDI
volumes on the array is shown in Table 4
17 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 4 Dell Storage PS4210XS layout for volumes hosting virtual desktops
Volume name Size Purpose
View-Replicas1 and 2 100 GB each Storage for base image for VDI deployment
VDI-Images1 through 8 500 GB each Storage for VDI VMs in VDI Cluster Each volume hosted 100 desktops
44 vSphere host network configuration VMware vSphere 55 hypervisor was installed on all servers The network configuration on each of those
hosts is described here Each vSphere host was configured with five virtual switches vSwitch0 vSwitch1
vSwitch2 vSwitch3 and vSwitch4 to separate different types of traffic on the system
Table 5 vSwitch configuration in vSphere hosts
vSwitch Description
vSwitch0 Management Network
vSwitch1 and vSwitch2 iSCSI SAN
vSwitch3 Fluid Cache VLAN
vSwitch4 VDI LAN
For additional information about individual vSwitch configuration refer to Appendix B in the Dell technical
white paper
45 Horizon view configuration Horizon View 60 was installed by using the documentation provided by VMware
Horizon View 601 installation documentation
httpswwwvmwarecomsupportpubsview_pubshtml
Table 6 Specific configuration used in the tests
Purpose Count Type Memory CPU
Horizon View Connection Servers
2 VM 16 GB 8nos
View Composer Server 1 VM 8 GB 8nos
18 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
46 Windows 7 VM configuration Following the guidelines from VMware and Login VSI the Windows 7 base image was generated based on
a generic base VM with the following properties
VMware Virtual Hardware version 8
Two virtual CPU
3 GB RAM with 15GB reserved
25 GB virtual hard drive
One virtual NIC connected to the VDI network
Windows 7 64-bit OS
Also the base image was customized by using the VMware Horizon with View Optimization Guide for
Windows 7 and Windows 8 available at this location httpwwwvmwarecomfilespdfVMware-View-
OptimizationGuideWindows7-ENpdf
19 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
5 Horizon view test methodology This section outlines the test objectives along with the test tools and criteria used to determine the
optimal virtual desktop density and best practices for deploying Horizon View on Dell Fluid Cache for SAN
for high IOPS type VDI environment
51 Test objectives As noted in Section 11 the test objectives were
Develop an optimal end-to-end infrastructure design for a Horizon View and vSpherendashbased high
user type of VDI solution deployed by using the Fluid Cache Compellent storage PowerEdge
servers and Dell Networking switches
Determine the performance at every layer of the VDI solution stack under high IOPS workload For
example desktops generating 80ndash90 IOPSVM at steady state
Determine the performance impact of peak IO activity such as boot and login storms
52 Test tools All tests were conducted by using Login VSI 40 as the workload generator and user experience analyzer
tool Login VSI is a benchmarking tool to measure the performance and scalability of centralized desktop
environments such as Server Based Computing (SBC) and VDI
Note More information can be found at the Login VSI website httpwwwloginvsicom
In addition to Login VSI Iometer is used in desktop VMs to simulate high IOPS conditions Iometer is
invoked in desktop VMs by using custom scripting of Login VSI workloads
Note More information can be found at the Iometer project website httpwwwiometerorg
521 Load generation First the ldquoMediumrdquo workload from Login VSI was used to simulate the standard user workload The
characteristics of the Medium workload are
Up to five applications are started simultaneously
Applications include Microsoft Internet Explorer Microsoft Word Microsoft Excel Microsoft
PowerPoint PDF reader 7-Zip compression software Movie player and FreeMind
After a session is started the medium workload repeats approximately after every 48 minutes
During a loop the response time is measured after every 3ndash4 minutes
Idle time is about two minutes in each 48-minute loop
Type rate is approximately 160 milliseconds per character
After the test by using Login VSI Medium was complete tests were rerun with Login VSI Medium and
Iometer in desktop VMs to simulate high IOPS VDI workload While the Login VSI Medium generates 8ndash10
20 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
IOPSVM the latter method was able to generate 80ndash90 IOPSVM For these tests each VM in the Horizon
view pool is created with standard LoginVSI contents and applications Also Iometer is installed on each
VM After the user logs in a customized logon script starts the Iometer with required IO specification (icf
file)
522 Monitoring tools The following monitoring tools were used
Dell Compellent Enterprise Manager for monitoring Fluid Cache and Compellent SC8000 storage
array performance
VMware vCenter statistics for vSphere performance
Login VSI Analyzer for end user performance statistics
Detailed performance metrics were captured from the storage arrays hypervisors virtual desktops and
the load generators during the tests
53 Test criteria The primary focus of the tests is to validate the 800 desktop high IOPS type of VDI architecture with
acceptable user experience by using Fluid Cache for SAN VDI configurations involve many components at
different layers ndash application hypervisor server network and storage As a result multiple metrics need to
be captured at different layers to ensure that the environment is healthy and performing optimally and
appropriately for all users
The specific test criteria are described in the following sections
531 Storage capacity and IO latency The typical industry standard latency limit for storage disk IO is 10 milliseconds Maintaining this limit
ensures good user application response times when there are no other bottlenecks at the infrastructure
layer In addition Dell recommends to maintain a 10 percent spare disk space on the storage array for
optimal performance
532 System utilization at the hypervisor Even though the primary focus of these tests was storage characterization additional metrics at the
hypervisor infrastructure layer were defined to ensure solution consistency These were
CPU utilization on any vSphere server must not exceed 85 percent
Minimal memory ballooning on the VMs
Total network bandwidth utilization must not exceed 90 percent on any one link
TCPIP storage network retransmissions should be less than 05 percent
21 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
533 Virtual desktop user experience Login VSI Analyzer was also used to gather metrics on the user experience at the virtual desktop layer to
ensure that all the desktops had acceptable levels of application performance Login VSI uses the VSImax
parameter to determine the maximum number of sessions that can be obtained from a deployed solution
The calculation methodology used in VSImax is available here
httpwwwloginvsicomdocumentationindexphptitle=Analyzing_Results
534 Test configuration A single virtual desktop pool was configured by using the VMware Horizon View Administrator interface
Each pool was built from a Windows 7 base image The Windows 7 configuration information is available
in Section 46
Desktop pool properties
Automatic Desktop Pool
Users are assigned using Floating assignments
View Storage Accelerator is enabled for all hosts with a refresh period of seven days
800 desktops were deployed across eight hosts (100 desktops a host)
Replica images were stored on a separate volume
22 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
6 Test results and analysis This section presents the results from the different Horizon View VDI characterization tests and the key
findings from each test The testing was focused on the high IOPS workload profile
61 Test scenarios The following tests were conducted to gather results and analysis on the solution stack
1 Boot storm Boot storms represent the worst-case scenario where many virtual desktops are
turned on at the same time and they all contend for the system resources simultaneously This test
was used to evaluate if the storage array hosting the desktops was capable of handling huge
variation in storage IO without causing significant impact on other services
2 Login storm Login storms also represent a high IOPS situation where many users are logging in to
their virtual desktops at the beginning of a workday or a shift In this test all the desktops were
pre-booted and left in an idle state for more than 20 minutes to let their IO settle before running
the Login VSI Medium workload to simulate users logging in to their virtual desktops
3 Steady state workload for standard users with normal IOPS After the login storm for the previous
test was completed the Login VSI Medium workload was allowed to run for at least one hour to
simulate the real-world scenario of users performing their daily tasks The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
4 Steady state workload for users with high IOPS The previous test was repeated with the Login
VSI Medium workload and Iometer scripts in desktop VMs as described in Section 521 to simulate
real-world heavy users performing their daily tasks with high IOPS The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
The following sections provide results from the boot storm login storm and steady state testing for the
Fluid Cache for SAN based VDI solution
23 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
62 Boot storm IO To simulate a boot storm the virtual desktops were reset simultaneously from the VMware vSphere client
Figure 6 shows the IO pattern on the Fluid Cache for the boot storm
Figure 6 SAN HQ data showing boot storm performance with Fluid Cache array
With 800 desktops the boot storm generated about 115000 total IOPS with a majority of them being
write operations All desktops were available for use in less than four minutes
24 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
63 Login storm and steady state for standard users (LoginVSI
Medium) Login VSI was programmed to start 800 virtual desktops over a period of about 60 minutes after pre-
booting the virtual desktops The peak IOPS during the login storm observed by the vSphere servers
hosting the desktops was about 6500 IOPS (8ndash10 IOPS a VM)
In a standard user environment login storms generate significantly more write IOPS than a boot storm or
steady state because of multiple factors such as
User profile activity
Starting operating system services on the desktop
First start of applications
After a virtual desktop has achieved a steady state after user login the Windows 7 OS has cached
applications in memory and does not need to access storage each time the application is started This
leads to lesser IOPS during the steady state Figure 7 here shows the various IO characteristics during the
login storm and steady state of these tests
25 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 7 IOPS and Cache Hit for the standard user test
On the Fluid Cache layer the maximum IOPS reached 6500 with cache-hit reaching 100 percent and
read-hit around 95 percent As shown in the Figure 8 here the throughput peaked at 98 MBps with a low
latency of less than 2 msec
26 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 8 Throughput and Latency for the standard user test
631 Server host performance During the login storm and steady state of the test the vSphere host CPU memory network and storage
performance were measured on all the servers that hosted the virtual desktops The performance of one
such vSphere server is given here The other vSphere servers had similar performance characteristics
Statistics for the vSphere hosts were captured by using VMware vCenter Server The figures here show the
CPU memory and network utilization for boot storm login storm and steady state of one of the vSphere
servers hosting the virtual desktops The results shown here are for a test run with 800 no standard user
desktops in the desktop pool
27 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 9 Average CPU performance per core on one vSphere host during login storm and steady state
Figure 10 Disk space usage during login storm and steady state
0
10
20
30
40
50
60
70
80
90
100
1020 1045 1110 1135 1200 1225
Per
cen
t
Time
CPU Performance
0
50
100
150
200
250
300
1020 1040 1100 1120 1140 1200 1220
GB
Time
Memory Performance
Granted Swap used Shared common
28 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 11 Overall network performance during login storm and steady state
Figure 12 Storage adapter performance during login storm and steady state
0
10000
20000
30000
40000
50000
60000
70000
1020 1045 1110 1135 1200 1225
kBp
s
Time
Network Performance
0
05
1
15
2
25
1020 1045 1110 1135 1200 1225
mSe
c
Time
Storage adaptor performance
29 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
The key observations from the statistics were
CPU utilization was less than the 85 percent threshold throughout the test
Active disk space usage was about 80 percent during the boost storm and about 60 percent
during login storm and steady state There was minimal-or no memory ballooning observed
Network utilization was about 45 percent which included all the networks such as iSCSI SAN VDI
LAN Management LAN and vMotion LAN
Average read- and write latencies at the storage adapter level were very close to the observed
latencies in Fluid Cache 2 msec
632 Monitoring user experience Figure 13 here shows the response time as experienced by each user as calculated by Login VSI The graph
clearly shows that the VSImax (Dynamic) value has not been reached and there were non-responsive or
inactive sessions This means that the array is capable of supporting the 1000 desktops and all users have
acceptable response times for applications that the user is has started
Figure 13 Login VSI user experience monitoring for 800 standard user desktops
30 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
633 Standard user test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SANndashbased VDI solution is able to host 800 virtual desktops and support
a standard user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only operations and
less than 2 percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to handle this login storm easily with low latency mdash it delivered the required 6500 IOPS with less
than 2 milliseconds of write latency with a 99 percent write VDI IO workload
64 Login storm and steady state with high IOPS (LoginVSI Medium +
Iometer) As mentioned earlier Iometer was used in desktop VMs alongside the Login VSI Medium workload to
simulate high IOPS type of VDI environment To mimic actual VDI workload profile the following Iometer
profile was used
20 KB block size 80 percent write 75 percent random with 25 msec burst delay
Figure 14 here shows the various IO characteristics during the login storm and steady state of these tests
Figure 14 IOPS and Cache Hit for the high IOPS test
On the Fluid Cache layer the maximum IOPS reached was approximately 72000 (or 90 IOPSVM) with
cache write-hit 100 percent and read-hit around 95 percent As shown in the Figure 15 the throughput
peaked at greater than 900 MBps with a peak latency of approximately 75 msec
31 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 15 Throughput and Latency for the high IOPS test
32 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
641 Server host performance Similar to the standard user test statistics for the vSphere hosts were captured by using VMware vCenter
Server during the high IOPS (heavy user) test also There are no significant differences in CPU disk space
and network utilization between standard users and heavy users The storage adapter latency is also
showing similar on hosts and observed on Fluid Cache
642 User experience monitoring Figure 16 here shows the response time as experienced by each user as calculated by Login VSI for the
heavy user test The graph shows that the VSImax (Dynamic) value was 796 indicating that the solution is
capable of supporting the 800 user high IOPS desktops with 90 IOPSVM
Figure 16 Login VSI user experience monitoring for 800 user high IOPS desktops
33 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
643 High IOPS (heavy user) test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SAN based VDI solution is able to host 800 virtual desktops and support a
high user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only and less than 2
percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to easily handle this login storm with low latency Subsequently it was able to handle 72000 IOPS
at high IOPS steady state with 90 IOPSVM with a maximum of 75 msec latency
34 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
7 Best practices This section provides the best practices derived from the testing and analysis in Section 6
71 Virtual Desktop Infrastructure This section provides best practices for the implementation of VDI using Dell Fluid Cache for SAN
711 Implement roaming profiles and folder redirection Dell recommends that all users in the VDI environment be configured with roaming profiles and folder
redirection This preserves user profiles and user data across boots while using non-persistent virtual
desktops
Also Dell recommends to use a high performance file service to provide the profile and folder redirection
A separate array may be used to host these volumes for best performance
712 Boot and login storm considerations Section 62 demonstrated the Fluid Cache for SAN performance under boot storm To avoid any potential
IO bursts because of boot storm and degraded user experience and performances Dell recommends that
all or portion of desktops be prebooted Connection brokers such as VMware Horizon View provide the
functionality to configure number of standby desktops
713 Windows 7 master image for desktop VMs Dell recommends that the operating system be customized in order to provide the best performance in a
VDI environment This includes disabling some services which may not be required This can improve
performance for the end user VMware has a specific set of recommendations and settings for Windows 7
and Windows 8 that allow for faster logins quicker screen refreshes and generally better performance
The VMware recommendations for Windows 7 and Windows 8 image optimization can be found here
httpwwwvmwarecomresourcestechresources10157
714 VDI Management infrastructure recommendations Dell recommends to have redundancy and load balancing for all VDI management services in the case of
VMware Horizon View solution as tested here the vSphere Server VMware Horizon View Servers and SQL
Servers Ideally these should be running on clustered hosts with VMware vSphere DRS (distributed
resource scheduler) and HA (high availability) enabled
72 Server host The vSphere servers hosting the infrastructure service providers and the virtual desktops are
recommended to be configured as follows
35 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Follow VMware and Dell best practices for installing and configuring vSphere
Separate virtual switches to segregate iSCSI SAN traffic VDI traffic vMotion traffic and Management
network traffic
Each network path must be assigned to a minimum of two physical NICs for high availability
VMware Knowledge Base article about best practices for installing vSphere 55
httpkbvmwarecomkb2052329
73 Network layer Dell recommends that at least two physical NICs on each vSphere server be dedicated to the VDI network
Use VLANs to segregate different types of network traffic on the same physical network In this case Dell
recommends to separate the infrastructure vMotion and VDI LAN traffic in to separate VLANs
Do not use VLANs to segregate iSCSI SAN and Fluide Cache traffic It is required that SAN and Cache traffic
be on separate dedicated physical network to provide the best performance
Virtual switches in vSphere have a default limit of 120 ports If the number of virtual desktops on each host
exceeds the available ports vSwitch properties should be changed to support the required number of
virtual desktops This change requires a restart of the host vSphere server
On iSCSI SAN switches Spanning tree must be disabled on switch ports connected to end devices for
server and storage ports The PortFast setting must be enabled in the switch configuration for these ports
Jumbo frames and Flow control (if the NICs support it) should be enabled for all components of the iSCSI
network
More information about configuring Dell Networking switches for use with Dell Storage iSCSI SANs is
available here
httpencommunitydellcomtechcenterstoragewwiki4250switch-configuration-guides-by-sisaspx
74 Storage The Dell SC storage arrays combined with Fluid Cache is an excellent platform for providing cost-effective
performance in VDI environments
Fluid Cache for SAN extends the power of Compellent intelligent data placement from the SAN to the
server By providing a single infrastructure for data at both high- and low ends of the performance
spectrum Fluid Cache for SAN with Storage Center 65 array software eliminates the tradeoffs between
server performance and full-featured SAN benefits such as reliability manageability and data protection
Dell recommends to have separate volumes for base image and virtual desktops This enables better
manageability of the volumes easier performance monitoring and allows easy future growth
Dell recommends to use a separate high performance file service to provide file shares for roaming
profiles and user shares
36 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
8 Conclusion The technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed by using a Horizon View VDI platform leveraging Dell Fluid Cache for SAN The storage IO
characteristics under various VDI workload scenarios (boot storm login storm and steady state) along
with performance characteristics throughout the VDI stack (for example vSphere server performance and
user experience) demonstrate the optimal configuration of the infrastructure used for this VDI
deployment For more information about Fluid Cache contact your Dell account manager
37 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
A Horizon view solution configuration
Table 7 Hardware components
Hardware components Description
Virtual Desktops 4 timesDell PowerEdge R720 Servers (Fluid Cache Providers)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
2times350 GB Dell Express Flash PCIe SSDs
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
4 x Dell PowerEdge R720 Servers (Fluid Cache Clients)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55 U2 on all R720 servers Windows 7 (64 Bit) VMs
Infrastructure Servers 2 x Dell PowerEdge R720 servers
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
96 GB RAM
2times300 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55U2 on all R720 servers VMs are loaded with Microsoft Windows 2008 R2
Active Directory
VMware Horizon View 60 Server 1
VMware Horizon View 60 Server 2
VMware vCenter Server 55 update 2
VMware Horizon View Composer
SQL Server
File Server
Login VSI Launchers 8 x Dell PowerEdge M610 servers
2timesIntelreg Xeonreg E-5503 200 GHz Processors
16 GB RAM
4times146 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57711 10GbE NIC
ESXi 51 installed on all R810 servers VMs are loaded with Microsoft Windows 7 64bit Each VM supports up to 30 Login VSI launcher sessions
38 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Network Management VDI LAN
1timesDell Force10 S55 1Gb Ethernet Switch
iSCSI SAN
1timesDell Force10 S4810 10Gb Ethernet Switch
Cache network
1timesDell Force10 S4810 10Gb Ethernet Switch
One Force10 S4810 switch might suffice for all the cache iSCSI SAN VDI LAN and management traffic
Storage 2timesDell Compellent SC8000 controllers 4times6Gb SAS 4-port PCI-E Full-height cards for back-end connectivity 2times10Gb iSCSI 2 port PCI-E Low-profile IO cards for front end connectivity 1timesDell Compellent SC200 disk enclosures 12times4TB NL-SAS 6Gb 72K 35rdquo drives
User Data Infrastructure VMs Virtual Desktops
Performance Monitoring
Dell Compellent Enterprise Manager Dell Fluid Cache for SAN performance monitoring tool () vCenter Performance monitoring Liquidware Stratusphere UX
Performance monitoring on Compellent arrays Fluid Cache performance monitoring Performance monitoring and capture at the ESXi host User experience monitoring on the virtual desktop
39 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 8 Software components
Software components Description Version
Dell Fluid Cache for SAN 20
Dell Compellent Storage Center 64
Dell Compellent Enterprise Manager 64
VMware Horizon View Server 60
VMware Horizon View Composer 60
VMware Horizon View Agent 60
VMware Horizon View Client 64-bit 60
VMware ESXi Hypervisor 55 U2
VMware vCenter Server 55 U2
Microsoft SQL Server 2008R2 Enterprise x64 105016001
Client VM OS Microsoft Windows 7 Enterprise x64 SP1
Management VM OS Microsoft Windows Server 2008 Enterprise R2 x64 SP1
Microsoft Office MS office 2010 Standard Service Pack 1
Login VSI Version 40
Iometer 20060727
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
13 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 3 Infrastructure Set-up for VDI Solution
1 Enterprise Manager Console 2 Management and VDI Client Network 3 vSphere Servers hosting virtual desktops 4 Cache network switches (2)
5 SAN switch 6 Storage Center controllers (2) 7 Storage Center expansion enclosures (2) 8 Server hosting VDI infrastructure VMs
(Server 1) (Server 2)
14 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
4 Solution configuration This section provides information about the solution configuration and test setup for hosting Horizon View
virtual desktops including infrastructure components networking and storage subsystems
41 Host design considerations The entire VDI solution was installed in two vSphere server clusters The clusters included
Figure 4 vSphere server clusters
Infrastructure Cluster Two Dell PowerEdge R720 servers hosting VMs for Active Directory
services VMware vCenter 55 server Horizon View Connection server (primary and secondary)
View Composer server Microsoft Windows Server 2012 R2 based file server and SQL Server 2012
R2
View Client Cluster Eight Dell PowerEdge R720 servers hosting the virtual desktops Each server
had
o 2times10 core Intel Xeon CPU E5-2690v2 300GHz
o 256 GB RAM
o 1times350 GB Dell Express Flash PCIe SSD
o 1timesMellanox Connect ndash X3 card
o 1timesDual-port Broadcom NetXtreme II BCM57810 10 Gigabit NIC
o 1timesQuad-port Broadcom NetXtreme BCM5720 Gigabit NIC
Along with the other servers the above servers 40 LoginVSI launcher VMs were used to generate VDI
workload They can be hosted by two PowerEdge R720 servers or equivalent for VDI load generation
purposes
15 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
42 Network design considerations Figure 5 here shows the network layout of one of the eight PowerEdge R720 servers with vSphere 55
installed
Figure 5 vSphere host network configuration
Three network switches are used in the Fluid Cache for VDI implementation One Force10 S55 1 GB switch
for all management traffic and VDI traffic The management traffic includes hosts and vSphere
management Compellent storage management and so on The networks are segregated by using VLANs
to separate different types of traffic
One Dell Force10 S4810 10 GB switch is used for Fluid Cache cache network which supports all the traffic
between cache layer on eight VDI VM hosts Another Force10 S4810 10 GB switch is used for iSCSI
network between infrastructure hosts VDI VM hosts and Compellent SC8000
Appendix B has extended information on the vSwitch configuration for each vSphere host
16 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
43 Dell Compellent SC8000 storage array configurations The storage used to host the virtual desktops was a Dell Compellent SC8000 array running Storage Center
Operating System (SCOS) 65 All two front-end ports were 10 GB iSCSI and all two back-end ports were
six GB serial-attached SCSI (SAS) The array used two external enclosures with Write Intensive (WI) SSDs
comprising Tier 1 and 15K SAS HDDs comprising Tier 2 for performance Also 72 NL-SAS drives were
used in Tier 3 to provide capacity for user data Table 2 summarizes the storage hardware configuration
Table 2 Storage hardware components
Storage role Type Qty Description
Controllers SC8000 2 System Center Operating System (SCOS) 65
Enclosures External 2 24 bay ndash 25rdquo disk drive enclosure
Ports Ethernet ndash 10 Gbps 2 Front end host connectivity
SAS - 6 Gbps 4 Back end drive connectivity
Drives 400 GB WI SSD 12 11 active with 1 hot spare
300 GB 15K SAS HDD
21 20 active with 1 hot spare
4 TB 72K NL-SAS HDD
12 11 active with 1 hot spare
The volumes created to host the virtual desktops took advantage of the Compellent Dynamic Capacity
technology for efficient capacity allocation Table 3 lists the volume layout used for the infrastructure
functions including user data
Table 3 Volume layout for hosting infrastructure components and user data
Volume name Size Purpose
Infrastructure 500 GB Storage for Active Directory SQL Server vCenter Server View Connection Server View Composer and File Server
UserSpace 2 TB Storage for User profiles and folder redirection space (Average 25 GB per user)
Along with the infrastructure volumes the storage array also provided shared storage for hosting the
virtual desktops The volume layout used for configuring the base image (View Composer Replica) and VDI
volumes on the array is shown in Table 4
17 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 4 Dell Storage PS4210XS layout for volumes hosting virtual desktops
Volume name Size Purpose
View-Replicas1 and 2 100 GB each Storage for base image for VDI deployment
VDI-Images1 through 8 500 GB each Storage for VDI VMs in VDI Cluster Each volume hosted 100 desktops
44 vSphere host network configuration VMware vSphere 55 hypervisor was installed on all servers The network configuration on each of those
hosts is described here Each vSphere host was configured with five virtual switches vSwitch0 vSwitch1
vSwitch2 vSwitch3 and vSwitch4 to separate different types of traffic on the system
Table 5 vSwitch configuration in vSphere hosts
vSwitch Description
vSwitch0 Management Network
vSwitch1 and vSwitch2 iSCSI SAN
vSwitch3 Fluid Cache VLAN
vSwitch4 VDI LAN
For additional information about individual vSwitch configuration refer to Appendix B in the Dell technical
white paper
45 Horizon view configuration Horizon View 60 was installed by using the documentation provided by VMware
Horizon View 601 installation documentation
httpswwwvmwarecomsupportpubsview_pubshtml
Table 6 Specific configuration used in the tests
Purpose Count Type Memory CPU
Horizon View Connection Servers
2 VM 16 GB 8nos
View Composer Server 1 VM 8 GB 8nos
18 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
46 Windows 7 VM configuration Following the guidelines from VMware and Login VSI the Windows 7 base image was generated based on
a generic base VM with the following properties
VMware Virtual Hardware version 8
Two virtual CPU
3 GB RAM with 15GB reserved
25 GB virtual hard drive
One virtual NIC connected to the VDI network
Windows 7 64-bit OS
Also the base image was customized by using the VMware Horizon with View Optimization Guide for
Windows 7 and Windows 8 available at this location httpwwwvmwarecomfilespdfVMware-View-
OptimizationGuideWindows7-ENpdf
19 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
5 Horizon view test methodology This section outlines the test objectives along with the test tools and criteria used to determine the
optimal virtual desktop density and best practices for deploying Horizon View on Dell Fluid Cache for SAN
for high IOPS type VDI environment
51 Test objectives As noted in Section 11 the test objectives were
Develop an optimal end-to-end infrastructure design for a Horizon View and vSpherendashbased high
user type of VDI solution deployed by using the Fluid Cache Compellent storage PowerEdge
servers and Dell Networking switches
Determine the performance at every layer of the VDI solution stack under high IOPS workload For
example desktops generating 80ndash90 IOPSVM at steady state
Determine the performance impact of peak IO activity such as boot and login storms
52 Test tools All tests were conducted by using Login VSI 40 as the workload generator and user experience analyzer
tool Login VSI is a benchmarking tool to measure the performance and scalability of centralized desktop
environments such as Server Based Computing (SBC) and VDI
Note More information can be found at the Login VSI website httpwwwloginvsicom
In addition to Login VSI Iometer is used in desktop VMs to simulate high IOPS conditions Iometer is
invoked in desktop VMs by using custom scripting of Login VSI workloads
Note More information can be found at the Iometer project website httpwwwiometerorg
521 Load generation First the ldquoMediumrdquo workload from Login VSI was used to simulate the standard user workload The
characteristics of the Medium workload are
Up to five applications are started simultaneously
Applications include Microsoft Internet Explorer Microsoft Word Microsoft Excel Microsoft
PowerPoint PDF reader 7-Zip compression software Movie player and FreeMind
After a session is started the medium workload repeats approximately after every 48 minutes
During a loop the response time is measured after every 3ndash4 minutes
Idle time is about two minutes in each 48-minute loop
Type rate is approximately 160 milliseconds per character
After the test by using Login VSI Medium was complete tests were rerun with Login VSI Medium and
Iometer in desktop VMs to simulate high IOPS VDI workload While the Login VSI Medium generates 8ndash10
20 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
IOPSVM the latter method was able to generate 80ndash90 IOPSVM For these tests each VM in the Horizon
view pool is created with standard LoginVSI contents and applications Also Iometer is installed on each
VM After the user logs in a customized logon script starts the Iometer with required IO specification (icf
file)
522 Monitoring tools The following monitoring tools were used
Dell Compellent Enterprise Manager for monitoring Fluid Cache and Compellent SC8000 storage
array performance
VMware vCenter statistics for vSphere performance
Login VSI Analyzer for end user performance statistics
Detailed performance metrics were captured from the storage arrays hypervisors virtual desktops and
the load generators during the tests
53 Test criteria The primary focus of the tests is to validate the 800 desktop high IOPS type of VDI architecture with
acceptable user experience by using Fluid Cache for SAN VDI configurations involve many components at
different layers ndash application hypervisor server network and storage As a result multiple metrics need to
be captured at different layers to ensure that the environment is healthy and performing optimally and
appropriately for all users
The specific test criteria are described in the following sections
531 Storage capacity and IO latency The typical industry standard latency limit for storage disk IO is 10 milliseconds Maintaining this limit
ensures good user application response times when there are no other bottlenecks at the infrastructure
layer In addition Dell recommends to maintain a 10 percent spare disk space on the storage array for
optimal performance
532 System utilization at the hypervisor Even though the primary focus of these tests was storage characterization additional metrics at the
hypervisor infrastructure layer were defined to ensure solution consistency These were
CPU utilization on any vSphere server must not exceed 85 percent
Minimal memory ballooning on the VMs
Total network bandwidth utilization must not exceed 90 percent on any one link
TCPIP storage network retransmissions should be less than 05 percent
21 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
533 Virtual desktop user experience Login VSI Analyzer was also used to gather metrics on the user experience at the virtual desktop layer to
ensure that all the desktops had acceptable levels of application performance Login VSI uses the VSImax
parameter to determine the maximum number of sessions that can be obtained from a deployed solution
The calculation methodology used in VSImax is available here
httpwwwloginvsicomdocumentationindexphptitle=Analyzing_Results
534 Test configuration A single virtual desktop pool was configured by using the VMware Horizon View Administrator interface
Each pool was built from a Windows 7 base image The Windows 7 configuration information is available
in Section 46
Desktop pool properties
Automatic Desktop Pool
Users are assigned using Floating assignments
View Storage Accelerator is enabled for all hosts with a refresh period of seven days
800 desktops were deployed across eight hosts (100 desktops a host)
Replica images were stored on a separate volume
22 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
6 Test results and analysis This section presents the results from the different Horizon View VDI characterization tests and the key
findings from each test The testing was focused on the high IOPS workload profile
61 Test scenarios The following tests were conducted to gather results and analysis on the solution stack
1 Boot storm Boot storms represent the worst-case scenario where many virtual desktops are
turned on at the same time and they all contend for the system resources simultaneously This test
was used to evaluate if the storage array hosting the desktops was capable of handling huge
variation in storage IO without causing significant impact on other services
2 Login storm Login storms also represent a high IOPS situation where many users are logging in to
their virtual desktops at the beginning of a workday or a shift In this test all the desktops were
pre-booted and left in an idle state for more than 20 minutes to let their IO settle before running
the Login VSI Medium workload to simulate users logging in to their virtual desktops
3 Steady state workload for standard users with normal IOPS After the login storm for the previous
test was completed the Login VSI Medium workload was allowed to run for at least one hour to
simulate the real-world scenario of users performing their daily tasks The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
4 Steady state workload for users with high IOPS The previous test was repeated with the Login
VSI Medium workload and Iometer scripts in desktop VMs as described in Section 521 to simulate
real-world heavy users performing their daily tasks with high IOPS The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
The following sections provide results from the boot storm login storm and steady state testing for the
Fluid Cache for SAN based VDI solution
23 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
62 Boot storm IO To simulate a boot storm the virtual desktops were reset simultaneously from the VMware vSphere client
Figure 6 shows the IO pattern on the Fluid Cache for the boot storm
Figure 6 SAN HQ data showing boot storm performance with Fluid Cache array
With 800 desktops the boot storm generated about 115000 total IOPS with a majority of them being
write operations All desktops were available for use in less than four minutes
24 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
63 Login storm and steady state for standard users (LoginVSI
Medium) Login VSI was programmed to start 800 virtual desktops over a period of about 60 minutes after pre-
booting the virtual desktops The peak IOPS during the login storm observed by the vSphere servers
hosting the desktops was about 6500 IOPS (8ndash10 IOPS a VM)
In a standard user environment login storms generate significantly more write IOPS than a boot storm or
steady state because of multiple factors such as
User profile activity
Starting operating system services on the desktop
First start of applications
After a virtual desktop has achieved a steady state after user login the Windows 7 OS has cached
applications in memory and does not need to access storage each time the application is started This
leads to lesser IOPS during the steady state Figure 7 here shows the various IO characteristics during the
login storm and steady state of these tests
25 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 7 IOPS and Cache Hit for the standard user test
On the Fluid Cache layer the maximum IOPS reached 6500 with cache-hit reaching 100 percent and
read-hit around 95 percent As shown in the Figure 8 here the throughput peaked at 98 MBps with a low
latency of less than 2 msec
26 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 8 Throughput and Latency for the standard user test
631 Server host performance During the login storm and steady state of the test the vSphere host CPU memory network and storage
performance were measured on all the servers that hosted the virtual desktops The performance of one
such vSphere server is given here The other vSphere servers had similar performance characteristics
Statistics for the vSphere hosts were captured by using VMware vCenter Server The figures here show the
CPU memory and network utilization for boot storm login storm and steady state of one of the vSphere
servers hosting the virtual desktops The results shown here are for a test run with 800 no standard user
desktops in the desktop pool
27 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 9 Average CPU performance per core on one vSphere host during login storm and steady state
Figure 10 Disk space usage during login storm and steady state
0
10
20
30
40
50
60
70
80
90
100
1020 1045 1110 1135 1200 1225
Per
cen
t
Time
CPU Performance
0
50
100
150
200
250
300
1020 1040 1100 1120 1140 1200 1220
GB
Time
Memory Performance
Granted Swap used Shared common
28 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 11 Overall network performance during login storm and steady state
Figure 12 Storage adapter performance during login storm and steady state
0
10000
20000
30000
40000
50000
60000
70000
1020 1045 1110 1135 1200 1225
kBp
s
Time
Network Performance
0
05
1
15
2
25
1020 1045 1110 1135 1200 1225
mSe
c
Time
Storage adaptor performance
29 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
The key observations from the statistics were
CPU utilization was less than the 85 percent threshold throughout the test
Active disk space usage was about 80 percent during the boost storm and about 60 percent
during login storm and steady state There was minimal-or no memory ballooning observed
Network utilization was about 45 percent which included all the networks such as iSCSI SAN VDI
LAN Management LAN and vMotion LAN
Average read- and write latencies at the storage adapter level were very close to the observed
latencies in Fluid Cache 2 msec
632 Monitoring user experience Figure 13 here shows the response time as experienced by each user as calculated by Login VSI The graph
clearly shows that the VSImax (Dynamic) value has not been reached and there were non-responsive or
inactive sessions This means that the array is capable of supporting the 1000 desktops and all users have
acceptable response times for applications that the user is has started
Figure 13 Login VSI user experience monitoring for 800 standard user desktops
30 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
633 Standard user test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SANndashbased VDI solution is able to host 800 virtual desktops and support
a standard user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only operations and
less than 2 percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to handle this login storm easily with low latency mdash it delivered the required 6500 IOPS with less
than 2 milliseconds of write latency with a 99 percent write VDI IO workload
64 Login storm and steady state with high IOPS (LoginVSI Medium +
Iometer) As mentioned earlier Iometer was used in desktop VMs alongside the Login VSI Medium workload to
simulate high IOPS type of VDI environment To mimic actual VDI workload profile the following Iometer
profile was used
20 KB block size 80 percent write 75 percent random with 25 msec burst delay
Figure 14 here shows the various IO characteristics during the login storm and steady state of these tests
Figure 14 IOPS and Cache Hit for the high IOPS test
On the Fluid Cache layer the maximum IOPS reached was approximately 72000 (or 90 IOPSVM) with
cache write-hit 100 percent and read-hit around 95 percent As shown in the Figure 15 the throughput
peaked at greater than 900 MBps with a peak latency of approximately 75 msec
31 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 15 Throughput and Latency for the high IOPS test
32 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
641 Server host performance Similar to the standard user test statistics for the vSphere hosts were captured by using VMware vCenter
Server during the high IOPS (heavy user) test also There are no significant differences in CPU disk space
and network utilization between standard users and heavy users The storage adapter latency is also
showing similar on hosts and observed on Fluid Cache
642 User experience monitoring Figure 16 here shows the response time as experienced by each user as calculated by Login VSI for the
heavy user test The graph shows that the VSImax (Dynamic) value was 796 indicating that the solution is
capable of supporting the 800 user high IOPS desktops with 90 IOPSVM
Figure 16 Login VSI user experience monitoring for 800 user high IOPS desktops
33 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
643 High IOPS (heavy user) test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SAN based VDI solution is able to host 800 virtual desktops and support a
high user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only and less than 2
percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to easily handle this login storm with low latency Subsequently it was able to handle 72000 IOPS
at high IOPS steady state with 90 IOPSVM with a maximum of 75 msec latency
34 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
7 Best practices This section provides the best practices derived from the testing and analysis in Section 6
71 Virtual Desktop Infrastructure This section provides best practices for the implementation of VDI using Dell Fluid Cache for SAN
711 Implement roaming profiles and folder redirection Dell recommends that all users in the VDI environment be configured with roaming profiles and folder
redirection This preserves user profiles and user data across boots while using non-persistent virtual
desktops
Also Dell recommends to use a high performance file service to provide the profile and folder redirection
A separate array may be used to host these volumes for best performance
712 Boot and login storm considerations Section 62 demonstrated the Fluid Cache for SAN performance under boot storm To avoid any potential
IO bursts because of boot storm and degraded user experience and performances Dell recommends that
all or portion of desktops be prebooted Connection brokers such as VMware Horizon View provide the
functionality to configure number of standby desktops
713 Windows 7 master image for desktop VMs Dell recommends that the operating system be customized in order to provide the best performance in a
VDI environment This includes disabling some services which may not be required This can improve
performance for the end user VMware has a specific set of recommendations and settings for Windows 7
and Windows 8 that allow for faster logins quicker screen refreshes and generally better performance
The VMware recommendations for Windows 7 and Windows 8 image optimization can be found here
httpwwwvmwarecomresourcestechresources10157
714 VDI Management infrastructure recommendations Dell recommends to have redundancy and load balancing for all VDI management services in the case of
VMware Horizon View solution as tested here the vSphere Server VMware Horizon View Servers and SQL
Servers Ideally these should be running on clustered hosts with VMware vSphere DRS (distributed
resource scheduler) and HA (high availability) enabled
72 Server host The vSphere servers hosting the infrastructure service providers and the virtual desktops are
recommended to be configured as follows
35 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Follow VMware and Dell best practices for installing and configuring vSphere
Separate virtual switches to segregate iSCSI SAN traffic VDI traffic vMotion traffic and Management
network traffic
Each network path must be assigned to a minimum of two physical NICs for high availability
VMware Knowledge Base article about best practices for installing vSphere 55
httpkbvmwarecomkb2052329
73 Network layer Dell recommends that at least two physical NICs on each vSphere server be dedicated to the VDI network
Use VLANs to segregate different types of network traffic on the same physical network In this case Dell
recommends to separate the infrastructure vMotion and VDI LAN traffic in to separate VLANs
Do not use VLANs to segregate iSCSI SAN and Fluide Cache traffic It is required that SAN and Cache traffic
be on separate dedicated physical network to provide the best performance
Virtual switches in vSphere have a default limit of 120 ports If the number of virtual desktops on each host
exceeds the available ports vSwitch properties should be changed to support the required number of
virtual desktops This change requires a restart of the host vSphere server
On iSCSI SAN switches Spanning tree must be disabled on switch ports connected to end devices for
server and storage ports The PortFast setting must be enabled in the switch configuration for these ports
Jumbo frames and Flow control (if the NICs support it) should be enabled for all components of the iSCSI
network
More information about configuring Dell Networking switches for use with Dell Storage iSCSI SANs is
available here
httpencommunitydellcomtechcenterstoragewwiki4250switch-configuration-guides-by-sisaspx
74 Storage The Dell SC storage arrays combined with Fluid Cache is an excellent platform for providing cost-effective
performance in VDI environments
Fluid Cache for SAN extends the power of Compellent intelligent data placement from the SAN to the
server By providing a single infrastructure for data at both high- and low ends of the performance
spectrum Fluid Cache for SAN with Storage Center 65 array software eliminates the tradeoffs between
server performance and full-featured SAN benefits such as reliability manageability and data protection
Dell recommends to have separate volumes for base image and virtual desktops This enables better
manageability of the volumes easier performance monitoring and allows easy future growth
Dell recommends to use a separate high performance file service to provide file shares for roaming
profiles and user shares
36 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
8 Conclusion The technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed by using a Horizon View VDI platform leveraging Dell Fluid Cache for SAN The storage IO
characteristics under various VDI workload scenarios (boot storm login storm and steady state) along
with performance characteristics throughout the VDI stack (for example vSphere server performance and
user experience) demonstrate the optimal configuration of the infrastructure used for this VDI
deployment For more information about Fluid Cache contact your Dell account manager
37 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
A Horizon view solution configuration
Table 7 Hardware components
Hardware components Description
Virtual Desktops 4 timesDell PowerEdge R720 Servers (Fluid Cache Providers)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
2times350 GB Dell Express Flash PCIe SSDs
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
4 x Dell PowerEdge R720 Servers (Fluid Cache Clients)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55 U2 on all R720 servers Windows 7 (64 Bit) VMs
Infrastructure Servers 2 x Dell PowerEdge R720 servers
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
96 GB RAM
2times300 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55U2 on all R720 servers VMs are loaded with Microsoft Windows 2008 R2
Active Directory
VMware Horizon View 60 Server 1
VMware Horizon View 60 Server 2
VMware vCenter Server 55 update 2
VMware Horizon View Composer
SQL Server
File Server
Login VSI Launchers 8 x Dell PowerEdge M610 servers
2timesIntelreg Xeonreg E-5503 200 GHz Processors
16 GB RAM
4times146 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57711 10GbE NIC
ESXi 51 installed on all R810 servers VMs are loaded with Microsoft Windows 7 64bit Each VM supports up to 30 Login VSI launcher sessions
38 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Network Management VDI LAN
1timesDell Force10 S55 1Gb Ethernet Switch
iSCSI SAN
1timesDell Force10 S4810 10Gb Ethernet Switch
Cache network
1timesDell Force10 S4810 10Gb Ethernet Switch
One Force10 S4810 switch might suffice for all the cache iSCSI SAN VDI LAN and management traffic
Storage 2timesDell Compellent SC8000 controllers 4times6Gb SAS 4-port PCI-E Full-height cards for back-end connectivity 2times10Gb iSCSI 2 port PCI-E Low-profile IO cards for front end connectivity 1timesDell Compellent SC200 disk enclosures 12times4TB NL-SAS 6Gb 72K 35rdquo drives
User Data Infrastructure VMs Virtual Desktops
Performance Monitoring
Dell Compellent Enterprise Manager Dell Fluid Cache for SAN performance monitoring tool () vCenter Performance monitoring Liquidware Stratusphere UX
Performance monitoring on Compellent arrays Fluid Cache performance monitoring Performance monitoring and capture at the ESXi host User experience monitoring on the virtual desktop
39 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 8 Software components
Software components Description Version
Dell Fluid Cache for SAN 20
Dell Compellent Storage Center 64
Dell Compellent Enterprise Manager 64
VMware Horizon View Server 60
VMware Horizon View Composer 60
VMware Horizon View Agent 60
VMware Horizon View Client 64-bit 60
VMware ESXi Hypervisor 55 U2
VMware vCenter Server 55 U2
Microsoft SQL Server 2008R2 Enterprise x64 105016001
Client VM OS Microsoft Windows 7 Enterprise x64 SP1
Management VM OS Microsoft Windows Server 2008 Enterprise R2 x64 SP1
Microsoft Office MS office 2010 Standard Service Pack 1
Login VSI Version 40
Iometer 20060727
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
14 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
4 Solution configuration This section provides information about the solution configuration and test setup for hosting Horizon View
virtual desktops including infrastructure components networking and storage subsystems
41 Host design considerations The entire VDI solution was installed in two vSphere server clusters The clusters included
Figure 4 vSphere server clusters
Infrastructure Cluster Two Dell PowerEdge R720 servers hosting VMs for Active Directory
services VMware vCenter 55 server Horizon View Connection server (primary and secondary)
View Composer server Microsoft Windows Server 2012 R2 based file server and SQL Server 2012
R2
View Client Cluster Eight Dell PowerEdge R720 servers hosting the virtual desktops Each server
had
o 2times10 core Intel Xeon CPU E5-2690v2 300GHz
o 256 GB RAM
o 1times350 GB Dell Express Flash PCIe SSD
o 1timesMellanox Connect ndash X3 card
o 1timesDual-port Broadcom NetXtreme II BCM57810 10 Gigabit NIC
o 1timesQuad-port Broadcom NetXtreme BCM5720 Gigabit NIC
Along with the other servers the above servers 40 LoginVSI launcher VMs were used to generate VDI
workload They can be hosted by two PowerEdge R720 servers or equivalent for VDI load generation
purposes
15 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
42 Network design considerations Figure 5 here shows the network layout of one of the eight PowerEdge R720 servers with vSphere 55
installed
Figure 5 vSphere host network configuration
Three network switches are used in the Fluid Cache for VDI implementation One Force10 S55 1 GB switch
for all management traffic and VDI traffic The management traffic includes hosts and vSphere
management Compellent storage management and so on The networks are segregated by using VLANs
to separate different types of traffic
One Dell Force10 S4810 10 GB switch is used for Fluid Cache cache network which supports all the traffic
between cache layer on eight VDI VM hosts Another Force10 S4810 10 GB switch is used for iSCSI
network between infrastructure hosts VDI VM hosts and Compellent SC8000
Appendix B has extended information on the vSwitch configuration for each vSphere host
16 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
43 Dell Compellent SC8000 storage array configurations The storage used to host the virtual desktops was a Dell Compellent SC8000 array running Storage Center
Operating System (SCOS) 65 All two front-end ports were 10 GB iSCSI and all two back-end ports were
six GB serial-attached SCSI (SAS) The array used two external enclosures with Write Intensive (WI) SSDs
comprising Tier 1 and 15K SAS HDDs comprising Tier 2 for performance Also 72 NL-SAS drives were
used in Tier 3 to provide capacity for user data Table 2 summarizes the storage hardware configuration
Table 2 Storage hardware components
Storage role Type Qty Description
Controllers SC8000 2 System Center Operating System (SCOS) 65
Enclosures External 2 24 bay ndash 25rdquo disk drive enclosure
Ports Ethernet ndash 10 Gbps 2 Front end host connectivity
SAS - 6 Gbps 4 Back end drive connectivity
Drives 400 GB WI SSD 12 11 active with 1 hot spare
300 GB 15K SAS HDD
21 20 active with 1 hot spare
4 TB 72K NL-SAS HDD
12 11 active with 1 hot spare
The volumes created to host the virtual desktops took advantage of the Compellent Dynamic Capacity
technology for efficient capacity allocation Table 3 lists the volume layout used for the infrastructure
functions including user data
Table 3 Volume layout for hosting infrastructure components and user data
Volume name Size Purpose
Infrastructure 500 GB Storage for Active Directory SQL Server vCenter Server View Connection Server View Composer and File Server
UserSpace 2 TB Storage for User profiles and folder redirection space (Average 25 GB per user)
Along with the infrastructure volumes the storage array also provided shared storage for hosting the
virtual desktops The volume layout used for configuring the base image (View Composer Replica) and VDI
volumes on the array is shown in Table 4
17 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 4 Dell Storage PS4210XS layout for volumes hosting virtual desktops
Volume name Size Purpose
View-Replicas1 and 2 100 GB each Storage for base image for VDI deployment
VDI-Images1 through 8 500 GB each Storage for VDI VMs in VDI Cluster Each volume hosted 100 desktops
44 vSphere host network configuration VMware vSphere 55 hypervisor was installed on all servers The network configuration on each of those
hosts is described here Each vSphere host was configured with five virtual switches vSwitch0 vSwitch1
vSwitch2 vSwitch3 and vSwitch4 to separate different types of traffic on the system
Table 5 vSwitch configuration in vSphere hosts
vSwitch Description
vSwitch0 Management Network
vSwitch1 and vSwitch2 iSCSI SAN
vSwitch3 Fluid Cache VLAN
vSwitch4 VDI LAN
For additional information about individual vSwitch configuration refer to Appendix B in the Dell technical
white paper
45 Horizon view configuration Horizon View 60 was installed by using the documentation provided by VMware
Horizon View 601 installation documentation
httpswwwvmwarecomsupportpubsview_pubshtml
Table 6 Specific configuration used in the tests
Purpose Count Type Memory CPU
Horizon View Connection Servers
2 VM 16 GB 8nos
View Composer Server 1 VM 8 GB 8nos
18 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
46 Windows 7 VM configuration Following the guidelines from VMware and Login VSI the Windows 7 base image was generated based on
a generic base VM with the following properties
VMware Virtual Hardware version 8
Two virtual CPU
3 GB RAM with 15GB reserved
25 GB virtual hard drive
One virtual NIC connected to the VDI network
Windows 7 64-bit OS
Also the base image was customized by using the VMware Horizon with View Optimization Guide for
Windows 7 and Windows 8 available at this location httpwwwvmwarecomfilespdfVMware-View-
OptimizationGuideWindows7-ENpdf
19 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
5 Horizon view test methodology This section outlines the test objectives along with the test tools and criteria used to determine the
optimal virtual desktop density and best practices for deploying Horizon View on Dell Fluid Cache for SAN
for high IOPS type VDI environment
51 Test objectives As noted in Section 11 the test objectives were
Develop an optimal end-to-end infrastructure design for a Horizon View and vSpherendashbased high
user type of VDI solution deployed by using the Fluid Cache Compellent storage PowerEdge
servers and Dell Networking switches
Determine the performance at every layer of the VDI solution stack under high IOPS workload For
example desktops generating 80ndash90 IOPSVM at steady state
Determine the performance impact of peak IO activity such as boot and login storms
52 Test tools All tests were conducted by using Login VSI 40 as the workload generator and user experience analyzer
tool Login VSI is a benchmarking tool to measure the performance and scalability of centralized desktop
environments such as Server Based Computing (SBC) and VDI
Note More information can be found at the Login VSI website httpwwwloginvsicom
In addition to Login VSI Iometer is used in desktop VMs to simulate high IOPS conditions Iometer is
invoked in desktop VMs by using custom scripting of Login VSI workloads
Note More information can be found at the Iometer project website httpwwwiometerorg
521 Load generation First the ldquoMediumrdquo workload from Login VSI was used to simulate the standard user workload The
characteristics of the Medium workload are
Up to five applications are started simultaneously
Applications include Microsoft Internet Explorer Microsoft Word Microsoft Excel Microsoft
PowerPoint PDF reader 7-Zip compression software Movie player and FreeMind
After a session is started the medium workload repeats approximately after every 48 minutes
During a loop the response time is measured after every 3ndash4 minutes
Idle time is about two minutes in each 48-minute loop
Type rate is approximately 160 milliseconds per character
After the test by using Login VSI Medium was complete tests were rerun with Login VSI Medium and
Iometer in desktop VMs to simulate high IOPS VDI workload While the Login VSI Medium generates 8ndash10
20 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
IOPSVM the latter method was able to generate 80ndash90 IOPSVM For these tests each VM in the Horizon
view pool is created with standard LoginVSI contents and applications Also Iometer is installed on each
VM After the user logs in a customized logon script starts the Iometer with required IO specification (icf
file)
522 Monitoring tools The following monitoring tools were used
Dell Compellent Enterprise Manager for monitoring Fluid Cache and Compellent SC8000 storage
array performance
VMware vCenter statistics for vSphere performance
Login VSI Analyzer for end user performance statistics
Detailed performance metrics were captured from the storage arrays hypervisors virtual desktops and
the load generators during the tests
53 Test criteria The primary focus of the tests is to validate the 800 desktop high IOPS type of VDI architecture with
acceptable user experience by using Fluid Cache for SAN VDI configurations involve many components at
different layers ndash application hypervisor server network and storage As a result multiple metrics need to
be captured at different layers to ensure that the environment is healthy and performing optimally and
appropriately for all users
The specific test criteria are described in the following sections
531 Storage capacity and IO latency The typical industry standard latency limit for storage disk IO is 10 milliseconds Maintaining this limit
ensures good user application response times when there are no other bottlenecks at the infrastructure
layer In addition Dell recommends to maintain a 10 percent spare disk space on the storage array for
optimal performance
532 System utilization at the hypervisor Even though the primary focus of these tests was storage characterization additional metrics at the
hypervisor infrastructure layer were defined to ensure solution consistency These were
CPU utilization on any vSphere server must not exceed 85 percent
Minimal memory ballooning on the VMs
Total network bandwidth utilization must not exceed 90 percent on any one link
TCPIP storage network retransmissions should be less than 05 percent
21 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
533 Virtual desktop user experience Login VSI Analyzer was also used to gather metrics on the user experience at the virtual desktop layer to
ensure that all the desktops had acceptable levels of application performance Login VSI uses the VSImax
parameter to determine the maximum number of sessions that can be obtained from a deployed solution
The calculation methodology used in VSImax is available here
httpwwwloginvsicomdocumentationindexphptitle=Analyzing_Results
534 Test configuration A single virtual desktop pool was configured by using the VMware Horizon View Administrator interface
Each pool was built from a Windows 7 base image The Windows 7 configuration information is available
in Section 46
Desktop pool properties
Automatic Desktop Pool
Users are assigned using Floating assignments
View Storage Accelerator is enabled for all hosts with a refresh period of seven days
800 desktops were deployed across eight hosts (100 desktops a host)
Replica images were stored on a separate volume
22 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
6 Test results and analysis This section presents the results from the different Horizon View VDI characterization tests and the key
findings from each test The testing was focused on the high IOPS workload profile
61 Test scenarios The following tests were conducted to gather results and analysis on the solution stack
1 Boot storm Boot storms represent the worst-case scenario where many virtual desktops are
turned on at the same time and they all contend for the system resources simultaneously This test
was used to evaluate if the storage array hosting the desktops was capable of handling huge
variation in storage IO without causing significant impact on other services
2 Login storm Login storms also represent a high IOPS situation where many users are logging in to
their virtual desktops at the beginning of a workday or a shift In this test all the desktops were
pre-booted and left in an idle state for more than 20 minutes to let their IO settle before running
the Login VSI Medium workload to simulate users logging in to their virtual desktops
3 Steady state workload for standard users with normal IOPS After the login storm for the previous
test was completed the Login VSI Medium workload was allowed to run for at least one hour to
simulate the real-world scenario of users performing their daily tasks The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
4 Steady state workload for users with high IOPS The previous test was repeated with the Login
VSI Medium workload and Iometer scripts in desktop VMs as described in Section 521 to simulate
real-world heavy users performing their daily tasks with high IOPS The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
The following sections provide results from the boot storm login storm and steady state testing for the
Fluid Cache for SAN based VDI solution
23 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
62 Boot storm IO To simulate a boot storm the virtual desktops were reset simultaneously from the VMware vSphere client
Figure 6 shows the IO pattern on the Fluid Cache for the boot storm
Figure 6 SAN HQ data showing boot storm performance with Fluid Cache array
With 800 desktops the boot storm generated about 115000 total IOPS with a majority of them being
write operations All desktops were available for use in less than four minutes
24 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
63 Login storm and steady state for standard users (LoginVSI
Medium) Login VSI was programmed to start 800 virtual desktops over a period of about 60 minutes after pre-
booting the virtual desktops The peak IOPS during the login storm observed by the vSphere servers
hosting the desktops was about 6500 IOPS (8ndash10 IOPS a VM)
In a standard user environment login storms generate significantly more write IOPS than a boot storm or
steady state because of multiple factors such as
User profile activity
Starting operating system services on the desktop
First start of applications
After a virtual desktop has achieved a steady state after user login the Windows 7 OS has cached
applications in memory and does not need to access storage each time the application is started This
leads to lesser IOPS during the steady state Figure 7 here shows the various IO characteristics during the
login storm and steady state of these tests
25 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 7 IOPS and Cache Hit for the standard user test
On the Fluid Cache layer the maximum IOPS reached 6500 with cache-hit reaching 100 percent and
read-hit around 95 percent As shown in the Figure 8 here the throughput peaked at 98 MBps with a low
latency of less than 2 msec
26 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 8 Throughput and Latency for the standard user test
631 Server host performance During the login storm and steady state of the test the vSphere host CPU memory network and storage
performance were measured on all the servers that hosted the virtual desktops The performance of one
such vSphere server is given here The other vSphere servers had similar performance characteristics
Statistics for the vSphere hosts were captured by using VMware vCenter Server The figures here show the
CPU memory and network utilization for boot storm login storm and steady state of one of the vSphere
servers hosting the virtual desktops The results shown here are for a test run with 800 no standard user
desktops in the desktop pool
27 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 9 Average CPU performance per core on one vSphere host during login storm and steady state
Figure 10 Disk space usage during login storm and steady state
0
10
20
30
40
50
60
70
80
90
100
1020 1045 1110 1135 1200 1225
Per
cen
t
Time
CPU Performance
0
50
100
150
200
250
300
1020 1040 1100 1120 1140 1200 1220
GB
Time
Memory Performance
Granted Swap used Shared common
28 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 11 Overall network performance during login storm and steady state
Figure 12 Storage adapter performance during login storm and steady state
0
10000
20000
30000
40000
50000
60000
70000
1020 1045 1110 1135 1200 1225
kBp
s
Time
Network Performance
0
05
1
15
2
25
1020 1045 1110 1135 1200 1225
mSe
c
Time
Storage adaptor performance
29 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
The key observations from the statistics were
CPU utilization was less than the 85 percent threshold throughout the test
Active disk space usage was about 80 percent during the boost storm and about 60 percent
during login storm and steady state There was minimal-or no memory ballooning observed
Network utilization was about 45 percent which included all the networks such as iSCSI SAN VDI
LAN Management LAN and vMotion LAN
Average read- and write latencies at the storage adapter level were very close to the observed
latencies in Fluid Cache 2 msec
632 Monitoring user experience Figure 13 here shows the response time as experienced by each user as calculated by Login VSI The graph
clearly shows that the VSImax (Dynamic) value has not been reached and there were non-responsive or
inactive sessions This means that the array is capable of supporting the 1000 desktops and all users have
acceptable response times for applications that the user is has started
Figure 13 Login VSI user experience monitoring for 800 standard user desktops
30 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
633 Standard user test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SANndashbased VDI solution is able to host 800 virtual desktops and support
a standard user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only operations and
less than 2 percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to handle this login storm easily with low latency mdash it delivered the required 6500 IOPS with less
than 2 milliseconds of write latency with a 99 percent write VDI IO workload
64 Login storm and steady state with high IOPS (LoginVSI Medium +
Iometer) As mentioned earlier Iometer was used in desktop VMs alongside the Login VSI Medium workload to
simulate high IOPS type of VDI environment To mimic actual VDI workload profile the following Iometer
profile was used
20 KB block size 80 percent write 75 percent random with 25 msec burst delay
Figure 14 here shows the various IO characteristics during the login storm and steady state of these tests
Figure 14 IOPS and Cache Hit for the high IOPS test
On the Fluid Cache layer the maximum IOPS reached was approximately 72000 (or 90 IOPSVM) with
cache write-hit 100 percent and read-hit around 95 percent As shown in the Figure 15 the throughput
peaked at greater than 900 MBps with a peak latency of approximately 75 msec
31 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 15 Throughput and Latency for the high IOPS test
32 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
641 Server host performance Similar to the standard user test statistics for the vSphere hosts were captured by using VMware vCenter
Server during the high IOPS (heavy user) test also There are no significant differences in CPU disk space
and network utilization between standard users and heavy users The storage adapter latency is also
showing similar on hosts and observed on Fluid Cache
642 User experience monitoring Figure 16 here shows the response time as experienced by each user as calculated by Login VSI for the
heavy user test The graph shows that the VSImax (Dynamic) value was 796 indicating that the solution is
capable of supporting the 800 user high IOPS desktops with 90 IOPSVM
Figure 16 Login VSI user experience monitoring for 800 user high IOPS desktops
33 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
643 High IOPS (heavy user) test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SAN based VDI solution is able to host 800 virtual desktops and support a
high user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only and less than 2
percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to easily handle this login storm with low latency Subsequently it was able to handle 72000 IOPS
at high IOPS steady state with 90 IOPSVM with a maximum of 75 msec latency
34 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
7 Best practices This section provides the best practices derived from the testing and analysis in Section 6
71 Virtual Desktop Infrastructure This section provides best practices for the implementation of VDI using Dell Fluid Cache for SAN
711 Implement roaming profiles and folder redirection Dell recommends that all users in the VDI environment be configured with roaming profiles and folder
redirection This preserves user profiles and user data across boots while using non-persistent virtual
desktops
Also Dell recommends to use a high performance file service to provide the profile and folder redirection
A separate array may be used to host these volumes for best performance
712 Boot and login storm considerations Section 62 demonstrated the Fluid Cache for SAN performance under boot storm To avoid any potential
IO bursts because of boot storm and degraded user experience and performances Dell recommends that
all or portion of desktops be prebooted Connection brokers such as VMware Horizon View provide the
functionality to configure number of standby desktops
713 Windows 7 master image for desktop VMs Dell recommends that the operating system be customized in order to provide the best performance in a
VDI environment This includes disabling some services which may not be required This can improve
performance for the end user VMware has a specific set of recommendations and settings for Windows 7
and Windows 8 that allow for faster logins quicker screen refreshes and generally better performance
The VMware recommendations for Windows 7 and Windows 8 image optimization can be found here
httpwwwvmwarecomresourcestechresources10157
714 VDI Management infrastructure recommendations Dell recommends to have redundancy and load balancing for all VDI management services in the case of
VMware Horizon View solution as tested here the vSphere Server VMware Horizon View Servers and SQL
Servers Ideally these should be running on clustered hosts with VMware vSphere DRS (distributed
resource scheduler) and HA (high availability) enabled
72 Server host The vSphere servers hosting the infrastructure service providers and the virtual desktops are
recommended to be configured as follows
35 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Follow VMware and Dell best practices for installing and configuring vSphere
Separate virtual switches to segregate iSCSI SAN traffic VDI traffic vMotion traffic and Management
network traffic
Each network path must be assigned to a minimum of two physical NICs for high availability
VMware Knowledge Base article about best practices for installing vSphere 55
httpkbvmwarecomkb2052329
73 Network layer Dell recommends that at least two physical NICs on each vSphere server be dedicated to the VDI network
Use VLANs to segregate different types of network traffic on the same physical network In this case Dell
recommends to separate the infrastructure vMotion and VDI LAN traffic in to separate VLANs
Do not use VLANs to segregate iSCSI SAN and Fluide Cache traffic It is required that SAN and Cache traffic
be on separate dedicated physical network to provide the best performance
Virtual switches in vSphere have a default limit of 120 ports If the number of virtual desktops on each host
exceeds the available ports vSwitch properties should be changed to support the required number of
virtual desktops This change requires a restart of the host vSphere server
On iSCSI SAN switches Spanning tree must be disabled on switch ports connected to end devices for
server and storage ports The PortFast setting must be enabled in the switch configuration for these ports
Jumbo frames and Flow control (if the NICs support it) should be enabled for all components of the iSCSI
network
More information about configuring Dell Networking switches for use with Dell Storage iSCSI SANs is
available here
httpencommunitydellcomtechcenterstoragewwiki4250switch-configuration-guides-by-sisaspx
74 Storage The Dell SC storage arrays combined with Fluid Cache is an excellent platform for providing cost-effective
performance in VDI environments
Fluid Cache for SAN extends the power of Compellent intelligent data placement from the SAN to the
server By providing a single infrastructure for data at both high- and low ends of the performance
spectrum Fluid Cache for SAN with Storage Center 65 array software eliminates the tradeoffs between
server performance and full-featured SAN benefits such as reliability manageability and data protection
Dell recommends to have separate volumes for base image and virtual desktops This enables better
manageability of the volumes easier performance monitoring and allows easy future growth
Dell recommends to use a separate high performance file service to provide file shares for roaming
profiles and user shares
36 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
8 Conclusion The technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed by using a Horizon View VDI platform leveraging Dell Fluid Cache for SAN The storage IO
characteristics under various VDI workload scenarios (boot storm login storm and steady state) along
with performance characteristics throughout the VDI stack (for example vSphere server performance and
user experience) demonstrate the optimal configuration of the infrastructure used for this VDI
deployment For more information about Fluid Cache contact your Dell account manager
37 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
A Horizon view solution configuration
Table 7 Hardware components
Hardware components Description
Virtual Desktops 4 timesDell PowerEdge R720 Servers (Fluid Cache Providers)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
2times350 GB Dell Express Flash PCIe SSDs
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
4 x Dell PowerEdge R720 Servers (Fluid Cache Clients)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55 U2 on all R720 servers Windows 7 (64 Bit) VMs
Infrastructure Servers 2 x Dell PowerEdge R720 servers
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
96 GB RAM
2times300 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55U2 on all R720 servers VMs are loaded with Microsoft Windows 2008 R2
Active Directory
VMware Horizon View 60 Server 1
VMware Horizon View 60 Server 2
VMware vCenter Server 55 update 2
VMware Horizon View Composer
SQL Server
File Server
Login VSI Launchers 8 x Dell PowerEdge M610 servers
2timesIntelreg Xeonreg E-5503 200 GHz Processors
16 GB RAM
4times146 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57711 10GbE NIC
ESXi 51 installed on all R810 servers VMs are loaded with Microsoft Windows 7 64bit Each VM supports up to 30 Login VSI launcher sessions
38 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Network Management VDI LAN
1timesDell Force10 S55 1Gb Ethernet Switch
iSCSI SAN
1timesDell Force10 S4810 10Gb Ethernet Switch
Cache network
1timesDell Force10 S4810 10Gb Ethernet Switch
One Force10 S4810 switch might suffice for all the cache iSCSI SAN VDI LAN and management traffic
Storage 2timesDell Compellent SC8000 controllers 4times6Gb SAS 4-port PCI-E Full-height cards for back-end connectivity 2times10Gb iSCSI 2 port PCI-E Low-profile IO cards for front end connectivity 1timesDell Compellent SC200 disk enclosures 12times4TB NL-SAS 6Gb 72K 35rdquo drives
User Data Infrastructure VMs Virtual Desktops
Performance Monitoring
Dell Compellent Enterprise Manager Dell Fluid Cache for SAN performance monitoring tool () vCenter Performance monitoring Liquidware Stratusphere UX
Performance monitoring on Compellent arrays Fluid Cache performance monitoring Performance monitoring and capture at the ESXi host User experience monitoring on the virtual desktop
39 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 8 Software components
Software components Description Version
Dell Fluid Cache for SAN 20
Dell Compellent Storage Center 64
Dell Compellent Enterprise Manager 64
VMware Horizon View Server 60
VMware Horizon View Composer 60
VMware Horizon View Agent 60
VMware Horizon View Client 64-bit 60
VMware ESXi Hypervisor 55 U2
VMware vCenter Server 55 U2
Microsoft SQL Server 2008R2 Enterprise x64 105016001
Client VM OS Microsoft Windows 7 Enterprise x64 SP1
Management VM OS Microsoft Windows Server 2008 Enterprise R2 x64 SP1
Microsoft Office MS office 2010 Standard Service Pack 1
Login VSI Version 40
Iometer 20060727
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
15 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
42 Network design considerations Figure 5 here shows the network layout of one of the eight PowerEdge R720 servers with vSphere 55
installed
Figure 5 vSphere host network configuration
Three network switches are used in the Fluid Cache for VDI implementation One Force10 S55 1 GB switch
for all management traffic and VDI traffic The management traffic includes hosts and vSphere
management Compellent storage management and so on The networks are segregated by using VLANs
to separate different types of traffic
One Dell Force10 S4810 10 GB switch is used for Fluid Cache cache network which supports all the traffic
between cache layer on eight VDI VM hosts Another Force10 S4810 10 GB switch is used for iSCSI
network between infrastructure hosts VDI VM hosts and Compellent SC8000
Appendix B has extended information on the vSwitch configuration for each vSphere host
16 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
43 Dell Compellent SC8000 storage array configurations The storage used to host the virtual desktops was a Dell Compellent SC8000 array running Storage Center
Operating System (SCOS) 65 All two front-end ports were 10 GB iSCSI and all two back-end ports were
six GB serial-attached SCSI (SAS) The array used two external enclosures with Write Intensive (WI) SSDs
comprising Tier 1 and 15K SAS HDDs comprising Tier 2 for performance Also 72 NL-SAS drives were
used in Tier 3 to provide capacity for user data Table 2 summarizes the storage hardware configuration
Table 2 Storage hardware components
Storage role Type Qty Description
Controllers SC8000 2 System Center Operating System (SCOS) 65
Enclosures External 2 24 bay ndash 25rdquo disk drive enclosure
Ports Ethernet ndash 10 Gbps 2 Front end host connectivity
SAS - 6 Gbps 4 Back end drive connectivity
Drives 400 GB WI SSD 12 11 active with 1 hot spare
300 GB 15K SAS HDD
21 20 active with 1 hot spare
4 TB 72K NL-SAS HDD
12 11 active with 1 hot spare
The volumes created to host the virtual desktops took advantage of the Compellent Dynamic Capacity
technology for efficient capacity allocation Table 3 lists the volume layout used for the infrastructure
functions including user data
Table 3 Volume layout for hosting infrastructure components and user data
Volume name Size Purpose
Infrastructure 500 GB Storage for Active Directory SQL Server vCenter Server View Connection Server View Composer and File Server
UserSpace 2 TB Storage for User profiles and folder redirection space (Average 25 GB per user)
Along with the infrastructure volumes the storage array also provided shared storage for hosting the
virtual desktops The volume layout used for configuring the base image (View Composer Replica) and VDI
volumes on the array is shown in Table 4
17 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 4 Dell Storage PS4210XS layout for volumes hosting virtual desktops
Volume name Size Purpose
View-Replicas1 and 2 100 GB each Storage for base image for VDI deployment
VDI-Images1 through 8 500 GB each Storage for VDI VMs in VDI Cluster Each volume hosted 100 desktops
44 vSphere host network configuration VMware vSphere 55 hypervisor was installed on all servers The network configuration on each of those
hosts is described here Each vSphere host was configured with five virtual switches vSwitch0 vSwitch1
vSwitch2 vSwitch3 and vSwitch4 to separate different types of traffic on the system
Table 5 vSwitch configuration in vSphere hosts
vSwitch Description
vSwitch0 Management Network
vSwitch1 and vSwitch2 iSCSI SAN
vSwitch3 Fluid Cache VLAN
vSwitch4 VDI LAN
For additional information about individual vSwitch configuration refer to Appendix B in the Dell technical
white paper
45 Horizon view configuration Horizon View 60 was installed by using the documentation provided by VMware
Horizon View 601 installation documentation
httpswwwvmwarecomsupportpubsview_pubshtml
Table 6 Specific configuration used in the tests
Purpose Count Type Memory CPU
Horizon View Connection Servers
2 VM 16 GB 8nos
View Composer Server 1 VM 8 GB 8nos
18 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
46 Windows 7 VM configuration Following the guidelines from VMware and Login VSI the Windows 7 base image was generated based on
a generic base VM with the following properties
VMware Virtual Hardware version 8
Two virtual CPU
3 GB RAM with 15GB reserved
25 GB virtual hard drive
One virtual NIC connected to the VDI network
Windows 7 64-bit OS
Also the base image was customized by using the VMware Horizon with View Optimization Guide for
Windows 7 and Windows 8 available at this location httpwwwvmwarecomfilespdfVMware-View-
OptimizationGuideWindows7-ENpdf
19 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
5 Horizon view test methodology This section outlines the test objectives along with the test tools and criteria used to determine the
optimal virtual desktop density and best practices for deploying Horizon View on Dell Fluid Cache for SAN
for high IOPS type VDI environment
51 Test objectives As noted in Section 11 the test objectives were
Develop an optimal end-to-end infrastructure design for a Horizon View and vSpherendashbased high
user type of VDI solution deployed by using the Fluid Cache Compellent storage PowerEdge
servers and Dell Networking switches
Determine the performance at every layer of the VDI solution stack under high IOPS workload For
example desktops generating 80ndash90 IOPSVM at steady state
Determine the performance impact of peak IO activity such as boot and login storms
52 Test tools All tests were conducted by using Login VSI 40 as the workload generator and user experience analyzer
tool Login VSI is a benchmarking tool to measure the performance and scalability of centralized desktop
environments such as Server Based Computing (SBC) and VDI
Note More information can be found at the Login VSI website httpwwwloginvsicom
In addition to Login VSI Iometer is used in desktop VMs to simulate high IOPS conditions Iometer is
invoked in desktop VMs by using custom scripting of Login VSI workloads
Note More information can be found at the Iometer project website httpwwwiometerorg
521 Load generation First the ldquoMediumrdquo workload from Login VSI was used to simulate the standard user workload The
characteristics of the Medium workload are
Up to five applications are started simultaneously
Applications include Microsoft Internet Explorer Microsoft Word Microsoft Excel Microsoft
PowerPoint PDF reader 7-Zip compression software Movie player and FreeMind
After a session is started the medium workload repeats approximately after every 48 minutes
During a loop the response time is measured after every 3ndash4 minutes
Idle time is about two minutes in each 48-minute loop
Type rate is approximately 160 milliseconds per character
After the test by using Login VSI Medium was complete tests were rerun with Login VSI Medium and
Iometer in desktop VMs to simulate high IOPS VDI workload While the Login VSI Medium generates 8ndash10
20 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
IOPSVM the latter method was able to generate 80ndash90 IOPSVM For these tests each VM in the Horizon
view pool is created with standard LoginVSI contents and applications Also Iometer is installed on each
VM After the user logs in a customized logon script starts the Iometer with required IO specification (icf
file)
522 Monitoring tools The following monitoring tools were used
Dell Compellent Enterprise Manager for monitoring Fluid Cache and Compellent SC8000 storage
array performance
VMware vCenter statistics for vSphere performance
Login VSI Analyzer for end user performance statistics
Detailed performance metrics were captured from the storage arrays hypervisors virtual desktops and
the load generators during the tests
53 Test criteria The primary focus of the tests is to validate the 800 desktop high IOPS type of VDI architecture with
acceptable user experience by using Fluid Cache for SAN VDI configurations involve many components at
different layers ndash application hypervisor server network and storage As a result multiple metrics need to
be captured at different layers to ensure that the environment is healthy and performing optimally and
appropriately for all users
The specific test criteria are described in the following sections
531 Storage capacity and IO latency The typical industry standard latency limit for storage disk IO is 10 milliseconds Maintaining this limit
ensures good user application response times when there are no other bottlenecks at the infrastructure
layer In addition Dell recommends to maintain a 10 percent spare disk space on the storage array for
optimal performance
532 System utilization at the hypervisor Even though the primary focus of these tests was storage characterization additional metrics at the
hypervisor infrastructure layer were defined to ensure solution consistency These were
CPU utilization on any vSphere server must not exceed 85 percent
Minimal memory ballooning on the VMs
Total network bandwidth utilization must not exceed 90 percent on any one link
TCPIP storage network retransmissions should be less than 05 percent
21 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
533 Virtual desktop user experience Login VSI Analyzer was also used to gather metrics on the user experience at the virtual desktop layer to
ensure that all the desktops had acceptable levels of application performance Login VSI uses the VSImax
parameter to determine the maximum number of sessions that can be obtained from a deployed solution
The calculation methodology used in VSImax is available here
httpwwwloginvsicomdocumentationindexphptitle=Analyzing_Results
534 Test configuration A single virtual desktop pool was configured by using the VMware Horizon View Administrator interface
Each pool was built from a Windows 7 base image The Windows 7 configuration information is available
in Section 46
Desktop pool properties
Automatic Desktop Pool
Users are assigned using Floating assignments
View Storage Accelerator is enabled for all hosts with a refresh period of seven days
800 desktops were deployed across eight hosts (100 desktops a host)
Replica images were stored on a separate volume
22 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
6 Test results and analysis This section presents the results from the different Horizon View VDI characterization tests and the key
findings from each test The testing was focused on the high IOPS workload profile
61 Test scenarios The following tests were conducted to gather results and analysis on the solution stack
1 Boot storm Boot storms represent the worst-case scenario where many virtual desktops are
turned on at the same time and they all contend for the system resources simultaneously This test
was used to evaluate if the storage array hosting the desktops was capable of handling huge
variation in storage IO without causing significant impact on other services
2 Login storm Login storms also represent a high IOPS situation where many users are logging in to
their virtual desktops at the beginning of a workday or a shift In this test all the desktops were
pre-booted and left in an idle state for more than 20 minutes to let their IO settle before running
the Login VSI Medium workload to simulate users logging in to their virtual desktops
3 Steady state workload for standard users with normal IOPS After the login storm for the previous
test was completed the Login VSI Medium workload was allowed to run for at least one hour to
simulate the real-world scenario of users performing their daily tasks The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
4 Steady state workload for users with high IOPS The previous test was repeated with the Login
VSI Medium workload and Iometer scripts in desktop VMs as described in Section 521 to simulate
real-world heavy users performing their daily tasks with high IOPS The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
The following sections provide results from the boot storm login storm and steady state testing for the
Fluid Cache for SAN based VDI solution
23 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
62 Boot storm IO To simulate a boot storm the virtual desktops were reset simultaneously from the VMware vSphere client
Figure 6 shows the IO pattern on the Fluid Cache for the boot storm
Figure 6 SAN HQ data showing boot storm performance with Fluid Cache array
With 800 desktops the boot storm generated about 115000 total IOPS with a majority of them being
write operations All desktops were available for use in less than four minutes
24 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
63 Login storm and steady state for standard users (LoginVSI
Medium) Login VSI was programmed to start 800 virtual desktops over a period of about 60 minutes after pre-
booting the virtual desktops The peak IOPS during the login storm observed by the vSphere servers
hosting the desktops was about 6500 IOPS (8ndash10 IOPS a VM)
In a standard user environment login storms generate significantly more write IOPS than a boot storm or
steady state because of multiple factors such as
User profile activity
Starting operating system services on the desktop
First start of applications
After a virtual desktop has achieved a steady state after user login the Windows 7 OS has cached
applications in memory and does not need to access storage each time the application is started This
leads to lesser IOPS during the steady state Figure 7 here shows the various IO characteristics during the
login storm and steady state of these tests
25 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 7 IOPS and Cache Hit for the standard user test
On the Fluid Cache layer the maximum IOPS reached 6500 with cache-hit reaching 100 percent and
read-hit around 95 percent As shown in the Figure 8 here the throughput peaked at 98 MBps with a low
latency of less than 2 msec
26 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 8 Throughput and Latency for the standard user test
631 Server host performance During the login storm and steady state of the test the vSphere host CPU memory network and storage
performance were measured on all the servers that hosted the virtual desktops The performance of one
such vSphere server is given here The other vSphere servers had similar performance characteristics
Statistics for the vSphere hosts were captured by using VMware vCenter Server The figures here show the
CPU memory and network utilization for boot storm login storm and steady state of one of the vSphere
servers hosting the virtual desktops The results shown here are for a test run with 800 no standard user
desktops in the desktop pool
27 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 9 Average CPU performance per core on one vSphere host during login storm and steady state
Figure 10 Disk space usage during login storm and steady state
0
10
20
30
40
50
60
70
80
90
100
1020 1045 1110 1135 1200 1225
Per
cen
t
Time
CPU Performance
0
50
100
150
200
250
300
1020 1040 1100 1120 1140 1200 1220
GB
Time
Memory Performance
Granted Swap used Shared common
28 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 11 Overall network performance during login storm and steady state
Figure 12 Storage adapter performance during login storm and steady state
0
10000
20000
30000
40000
50000
60000
70000
1020 1045 1110 1135 1200 1225
kBp
s
Time
Network Performance
0
05
1
15
2
25
1020 1045 1110 1135 1200 1225
mSe
c
Time
Storage adaptor performance
29 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
The key observations from the statistics were
CPU utilization was less than the 85 percent threshold throughout the test
Active disk space usage was about 80 percent during the boost storm and about 60 percent
during login storm and steady state There was minimal-or no memory ballooning observed
Network utilization was about 45 percent which included all the networks such as iSCSI SAN VDI
LAN Management LAN and vMotion LAN
Average read- and write latencies at the storage adapter level were very close to the observed
latencies in Fluid Cache 2 msec
632 Monitoring user experience Figure 13 here shows the response time as experienced by each user as calculated by Login VSI The graph
clearly shows that the VSImax (Dynamic) value has not been reached and there were non-responsive or
inactive sessions This means that the array is capable of supporting the 1000 desktops and all users have
acceptable response times for applications that the user is has started
Figure 13 Login VSI user experience monitoring for 800 standard user desktops
30 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
633 Standard user test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SANndashbased VDI solution is able to host 800 virtual desktops and support
a standard user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only operations and
less than 2 percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to handle this login storm easily with low latency mdash it delivered the required 6500 IOPS with less
than 2 milliseconds of write latency with a 99 percent write VDI IO workload
64 Login storm and steady state with high IOPS (LoginVSI Medium +
Iometer) As mentioned earlier Iometer was used in desktop VMs alongside the Login VSI Medium workload to
simulate high IOPS type of VDI environment To mimic actual VDI workload profile the following Iometer
profile was used
20 KB block size 80 percent write 75 percent random with 25 msec burst delay
Figure 14 here shows the various IO characteristics during the login storm and steady state of these tests
Figure 14 IOPS and Cache Hit for the high IOPS test
On the Fluid Cache layer the maximum IOPS reached was approximately 72000 (or 90 IOPSVM) with
cache write-hit 100 percent and read-hit around 95 percent As shown in the Figure 15 the throughput
peaked at greater than 900 MBps with a peak latency of approximately 75 msec
31 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 15 Throughput and Latency for the high IOPS test
32 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
641 Server host performance Similar to the standard user test statistics for the vSphere hosts were captured by using VMware vCenter
Server during the high IOPS (heavy user) test also There are no significant differences in CPU disk space
and network utilization between standard users and heavy users The storage adapter latency is also
showing similar on hosts and observed on Fluid Cache
642 User experience monitoring Figure 16 here shows the response time as experienced by each user as calculated by Login VSI for the
heavy user test The graph shows that the VSImax (Dynamic) value was 796 indicating that the solution is
capable of supporting the 800 user high IOPS desktops with 90 IOPSVM
Figure 16 Login VSI user experience monitoring for 800 user high IOPS desktops
33 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
643 High IOPS (heavy user) test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SAN based VDI solution is able to host 800 virtual desktops and support a
high user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only and less than 2
percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to easily handle this login storm with low latency Subsequently it was able to handle 72000 IOPS
at high IOPS steady state with 90 IOPSVM with a maximum of 75 msec latency
34 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
7 Best practices This section provides the best practices derived from the testing and analysis in Section 6
71 Virtual Desktop Infrastructure This section provides best practices for the implementation of VDI using Dell Fluid Cache for SAN
711 Implement roaming profiles and folder redirection Dell recommends that all users in the VDI environment be configured with roaming profiles and folder
redirection This preserves user profiles and user data across boots while using non-persistent virtual
desktops
Also Dell recommends to use a high performance file service to provide the profile and folder redirection
A separate array may be used to host these volumes for best performance
712 Boot and login storm considerations Section 62 demonstrated the Fluid Cache for SAN performance under boot storm To avoid any potential
IO bursts because of boot storm and degraded user experience and performances Dell recommends that
all or portion of desktops be prebooted Connection brokers such as VMware Horizon View provide the
functionality to configure number of standby desktops
713 Windows 7 master image for desktop VMs Dell recommends that the operating system be customized in order to provide the best performance in a
VDI environment This includes disabling some services which may not be required This can improve
performance for the end user VMware has a specific set of recommendations and settings for Windows 7
and Windows 8 that allow for faster logins quicker screen refreshes and generally better performance
The VMware recommendations for Windows 7 and Windows 8 image optimization can be found here
httpwwwvmwarecomresourcestechresources10157
714 VDI Management infrastructure recommendations Dell recommends to have redundancy and load balancing for all VDI management services in the case of
VMware Horizon View solution as tested here the vSphere Server VMware Horizon View Servers and SQL
Servers Ideally these should be running on clustered hosts with VMware vSphere DRS (distributed
resource scheduler) and HA (high availability) enabled
72 Server host The vSphere servers hosting the infrastructure service providers and the virtual desktops are
recommended to be configured as follows
35 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Follow VMware and Dell best practices for installing and configuring vSphere
Separate virtual switches to segregate iSCSI SAN traffic VDI traffic vMotion traffic and Management
network traffic
Each network path must be assigned to a minimum of two physical NICs for high availability
VMware Knowledge Base article about best practices for installing vSphere 55
httpkbvmwarecomkb2052329
73 Network layer Dell recommends that at least two physical NICs on each vSphere server be dedicated to the VDI network
Use VLANs to segregate different types of network traffic on the same physical network In this case Dell
recommends to separate the infrastructure vMotion and VDI LAN traffic in to separate VLANs
Do not use VLANs to segregate iSCSI SAN and Fluide Cache traffic It is required that SAN and Cache traffic
be on separate dedicated physical network to provide the best performance
Virtual switches in vSphere have a default limit of 120 ports If the number of virtual desktops on each host
exceeds the available ports vSwitch properties should be changed to support the required number of
virtual desktops This change requires a restart of the host vSphere server
On iSCSI SAN switches Spanning tree must be disabled on switch ports connected to end devices for
server and storage ports The PortFast setting must be enabled in the switch configuration for these ports
Jumbo frames and Flow control (if the NICs support it) should be enabled for all components of the iSCSI
network
More information about configuring Dell Networking switches for use with Dell Storage iSCSI SANs is
available here
httpencommunitydellcomtechcenterstoragewwiki4250switch-configuration-guides-by-sisaspx
74 Storage The Dell SC storage arrays combined with Fluid Cache is an excellent platform for providing cost-effective
performance in VDI environments
Fluid Cache for SAN extends the power of Compellent intelligent data placement from the SAN to the
server By providing a single infrastructure for data at both high- and low ends of the performance
spectrum Fluid Cache for SAN with Storage Center 65 array software eliminates the tradeoffs between
server performance and full-featured SAN benefits such as reliability manageability and data protection
Dell recommends to have separate volumes for base image and virtual desktops This enables better
manageability of the volumes easier performance monitoring and allows easy future growth
Dell recommends to use a separate high performance file service to provide file shares for roaming
profiles and user shares
36 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
8 Conclusion The technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed by using a Horizon View VDI platform leveraging Dell Fluid Cache for SAN The storage IO
characteristics under various VDI workload scenarios (boot storm login storm and steady state) along
with performance characteristics throughout the VDI stack (for example vSphere server performance and
user experience) demonstrate the optimal configuration of the infrastructure used for this VDI
deployment For more information about Fluid Cache contact your Dell account manager
37 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
A Horizon view solution configuration
Table 7 Hardware components
Hardware components Description
Virtual Desktops 4 timesDell PowerEdge R720 Servers (Fluid Cache Providers)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
2times350 GB Dell Express Flash PCIe SSDs
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
4 x Dell PowerEdge R720 Servers (Fluid Cache Clients)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55 U2 on all R720 servers Windows 7 (64 Bit) VMs
Infrastructure Servers 2 x Dell PowerEdge R720 servers
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
96 GB RAM
2times300 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55U2 on all R720 servers VMs are loaded with Microsoft Windows 2008 R2
Active Directory
VMware Horizon View 60 Server 1
VMware Horizon View 60 Server 2
VMware vCenter Server 55 update 2
VMware Horizon View Composer
SQL Server
File Server
Login VSI Launchers 8 x Dell PowerEdge M610 servers
2timesIntelreg Xeonreg E-5503 200 GHz Processors
16 GB RAM
4times146 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57711 10GbE NIC
ESXi 51 installed on all R810 servers VMs are loaded with Microsoft Windows 7 64bit Each VM supports up to 30 Login VSI launcher sessions
38 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Network Management VDI LAN
1timesDell Force10 S55 1Gb Ethernet Switch
iSCSI SAN
1timesDell Force10 S4810 10Gb Ethernet Switch
Cache network
1timesDell Force10 S4810 10Gb Ethernet Switch
One Force10 S4810 switch might suffice for all the cache iSCSI SAN VDI LAN and management traffic
Storage 2timesDell Compellent SC8000 controllers 4times6Gb SAS 4-port PCI-E Full-height cards for back-end connectivity 2times10Gb iSCSI 2 port PCI-E Low-profile IO cards for front end connectivity 1timesDell Compellent SC200 disk enclosures 12times4TB NL-SAS 6Gb 72K 35rdquo drives
User Data Infrastructure VMs Virtual Desktops
Performance Monitoring
Dell Compellent Enterprise Manager Dell Fluid Cache for SAN performance monitoring tool () vCenter Performance monitoring Liquidware Stratusphere UX
Performance monitoring on Compellent arrays Fluid Cache performance monitoring Performance monitoring and capture at the ESXi host User experience monitoring on the virtual desktop
39 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 8 Software components
Software components Description Version
Dell Fluid Cache for SAN 20
Dell Compellent Storage Center 64
Dell Compellent Enterprise Manager 64
VMware Horizon View Server 60
VMware Horizon View Composer 60
VMware Horizon View Agent 60
VMware Horizon View Client 64-bit 60
VMware ESXi Hypervisor 55 U2
VMware vCenter Server 55 U2
Microsoft SQL Server 2008R2 Enterprise x64 105016001
Client VM OS Microsoft Windows 7 Enterprise x64 SP1
Management VM OS Microsoft Windows Server 2008 Enterprise R2 x64 SP1
Microsoft Office MS office 2010 Standard Service Pack 1
Login VSI Version 40
Iometer 20060727
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
16 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
43 Dell Compellent SC8000 storage array configurations The storage used to host the virtual desktops was a Dell Compellent SC8000 array running Storage Center
Operating System (SCOS) 65 All two front-end ports were 10 GB iSCSI and all two back-end ports were
six GB serial-attached SCSI (SAS) The array used two external enclosures with Write Intensive (WI) SSDs
comprising Tier 1 and 15K SAS HDDs comprising Tier 2 for performance Also 72 NL-SAS drives were
used in Tier 3 to provide capacity for user data Table 2 summarizes the storage hardware configuration
Table 2 Storage hardware components
Storage role Type Qty Description
Controllers SC8000 2 System Center Operating System (SCOS) 65
Enclosures External 2 24 bay ndash 25rdquo disk drive enclosure
Ports Ethernet ndash 10 Gbps 2 Front end host connectivity
SAS - 6 Gbps 4 Back end drive connectivity
Drives 400 GB WI SSD 12 11 active with 1 hot spare
300 GB 15K SAS HDD
21 20 active with 1 hot spare
4 TB 72K NL-SAS HDD
12 11 active with 1 hot spare
The volumes created to host the virtual desktops took advantage of the Compellent Dynamic Capacity
technology for efficient capacity allocation Table 3 lists the volume layout used for the infrastructure
functions including user data
Table 3 Volume layout for hosting infrastructure components and user data
Volume name Size Purpose
Infrastructure 500 GB Storage for Active Directory SQL Server vCenter Server View Connection Server View Composer and File Server
UserSpace 2 TB Storage for User profiles and folder redirection space (Average 25 GB per user)
Along with the infrastructure volumes the storage array also provided shared storage for hosting the
virtual desktops The volume layout used for configuring the base image (View Composer Replica) and VDI
volumes on the array is shown in Table 4
17 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 4 Dell Storage PS4210XS layout for volumes hosting virtual desktops
Volume name Size Purpose
View-Replicas1 and 2 100 GB each Storage for base image for VDI deployment
VDI-Images1 through 8 500 GB each Storage for VDI VMs in VDI Cluster Each volume hosted 100 desktops
44 vSphere host network configuration VMware vSphere 55 hypervisor was installed on all servers The network configuration on each of those
hosts is described here Each vSphere host was configured with five virtual switches vSwitch0 vSwitch1
vSwitch2 vSwitch3 and vSwitch4 to separate different types of traffic on the system
Table 5 vSwitch configuration in vSphere hosts
vSwitch Description
vSwitch0 Management Network
vSwitch1 and vSwitch2 iSCSI SAN
vSwitch3 Fluid Cache VLAN
vSwitch4 VDI LAN
For additional information about individual vSwitch configuration refer to Appendix B in the Dell technical
white paper
45 Horizon view configuration Horizon View 60 was installed by using the documentation provided by VMware
Horizon View 601 installation documentation
httpswwwvmwarecomsupportpubsview_pubshtml
Table 6 Specific configuration used in the tests
Purpose Count Type Memory CPU
Horizon View Connection Servers
2 VM 16 GB 8nos
View Composer Server 1 VM 8 GB 8nos
18 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
46 Windows 7 VM configuration Following the guidelines from VMware and Login VSI the Windows 7 base image was generated based on
a generic base VM with the following properties
VMware Virtual Hardware version 8
Two virtual CPU
3 GB RAM with 15GB reserved
25 GB virtual hard drive
One virtual NIC connected to the VDI network
Windows 7 64-bit OS
Also the base image was customized by using the VMware Horizon with View Optimization Guide for
Windows 7 and Windows 8 available at this location httpwwwvmwarecomfilespdfVMware-View-
OptimizationGuideWindows7-ENpdf
19 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
5 Horizon view test methodology This section outlines the test objectives along with the test tools and criteria used to determine the
optimal virtual desktop density and best practices for deploying Horizon View on Dell Fluid Cache for SAN
for high IOPS type VDI environment
51 Test objectives As noted in Section 11 the test objectives were
Develop an optimal end-to-end infrastructure design for a Horizon View and vSpherendashbased high
user type of VDI solution deployed by using the Fluid Cache Compellent storage PowerEdge
servers and Dell Networking switches
Determine the performance at every layer of the VDI solution stack under high IOPS workload For
example desktops generating 80ndash90 IOPSVM at steady state
Determine the performance impact of peak IO activity such as boot and login storms
52 Test tools All tests were conducted by using Login VSI 40 as the workload generator and user experience analyzer
tool Login VSI is a benchmarking tool to measure the performance and scalability of centralized desktop
environments such as Server Based Computing (SBC) and VDI
Note More information can be found at the Login VSI website httpwwwloginvsicom
In addition to Login VSI Iometer is used in desktop VMs to simulate high IOPS conditions Iometer is
invoked in desktop VMs by using custom scripting of Login VSI workloads
Note More information can be found at the Iometer project website httpwwwiometerorg
521 Load generation First the ldquoMediumrdquo workload from Login VSI was used to simulate the standard user workload The
characteristics of the Medium workload are
Up to five applications are started simultaneously
Applications include Microsoft Internet Explorer Microsoft Word Microsoft Excel Microsoft
PowerPoint PDF reader 7-Zip compression software Movie player and FreeMind
After a session is started the medium workload repeats approximately after every 48 minutes
During a loop the response time is measured after every 3ndash4 minutes
Idle time is about two minutes in each 48-minute loop
Type rate is approximately 160 milliseconds per character
After the test by using Login VSI Medium was complete tests were rerun with Login VSI Medium and
Iometer in desktop VMs to simulate high IOPS VDI workload While the Login VSI Medium generates 8ndash10
20 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
IOPSVM the latter method was able to generate 80ndash90 IOPSVM For these tests each VM in the Horizon
view pool is created with standard LoginVSI contents and applications Also Iometer is installed on each
VM After the user logs in a customized logon script starts the Iometer with required IO specification (icf
file)
522 Monitoring tools The following monitoring tools were used
Dell Compellent Enterprise Manager for monitoring Fluid Cache and Compellent SC8000 storage
array performance
VMware vCenter statistics for vSphere performance
Login VSI Analyzer for end user performance statistics
Detailed performance metrics were captured from the storage arrays hypervisors virtual desktops and
the load generators during the tests
53 Test criteria The primary focus of the tests is to validate the 800 desktop high IOPS type of VDI architecture with
acceptable user experience by using Fluid Cache for SAN VDI configurations involve many components at
different layers ndash application hypervisor server network and storage As a result multiple metrics need to
be captured at different layers to ensure that the environment is healthy and performing optimally and
appropriately for all users
The specific test criteria are described in the following sections
531 Storage capacity and IO latency The typical industry standard latency limit for storage disk IO is 10 milliseconds Maintaining this limit
ensures good user application response times when there are no other bottlenecks at the infrastructure
layer In addition Dell recommends to maintain a 10 percent spare disk space on the storage array for
optimal performance
532 System utilization at the hypervisor Even though the primary focus of these tests was storage characterization additional metrics at the
hypervisor infrastructure layer were defined to ensure solution consistency These were
CPU utilization on any vSphere server must not exceed 85 percent
Minimal memory ballooning on the VMs
Total network bandwidth utilization must not exceed 90 percent on any one link
TCPIP storage network retransmissions should be less than 05 percent
21 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
533 Virtual desktop user experience Login VSI Analyzer was also used to gather metrics on the user experience at the virtual desktop layer to
ensure that all the desktops had acceptable levels of application performance Login VSI uses the VSImax
parameter to determine the maximum number of sessions that can be obtained from a deployed solution
The calculation methodology used in VSImax is available here
httpwwwloginvsicomdocumentationindexphptitle=Analyzing_Results
534 Test configuration A single virtual desktop pool was configured by using the VMware Horizon View Administrator interface
Each pool was built from a Windows 7 base image The Windows 7 configuration information is available
in Section 46
Desktop pool properties
Automatic Desktop Pool
Users are assigned using Floating assignments
View Storage Accelerator is enabled for all hosts with a refresh period of seven days
800 desktops were deployed across eight hosts (100 desktops a host)
Replica images were stored on a separate volume
22 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
6 Test results and analysis This section presents the results from the different Horizon View VDI characterization tests and the key
findings from each test The testing was focused on the high IOPS workload profile
61 Test scenarios The following tests were conducted to gather results and analysis on the solution stack
1 Boot storm Boot storms represent the worst-case scenario where many virtual desktops are
turned on at the same time and they all contend for the system resources simultaneously This test
was used to evaluate if the storage array hosting the desktops was capable of handling huge
variation in storage IO without causing significant impact on other services
2 Login storm Login storms also represent a high IOPS situation where many users are logging in to
their virtual desktops at the beginning of a workday or a shift In this test all the desktops were
pre-booted and left in an idle state for more than 20 minutes to let their IO settle before running
the Login VSI Medium workload to simulate users logging in to their virtual desktops
3 Steady state workload for standard users with normal IOPS After the login storm for the previous
test was completed the Login VSI Medium workload was allowed to run for at least one hour to
simulate the real-world scenario of users performing their daily tasks The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
4 Steady state workload for users with high IOPS The previous test was repeated with the Login
VSI Medium workload and Iometer scripts in desktop VMs as described in Section 521 to simulate
real-world heavy users performing their daily tasks with high IOPS The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
The following sections provide results from the boot storm login storm and steady state testing for the
Fluid Cache for SAN based VDI solution
23 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
62 Boot storm IO To simulate a boot storm the virtual desktops were reset simultaneously from the VMware vSphere client
Figure 6 shows the IO pattern on the Fluid Cache for the boot storm
Figure 6 SAN HQ data showing boot storm performance with Fluid Cache array
With 800 desktops the boot storm generated about 115000 total IOPS with a majority of them being
write operations All desktops were available for use in less than four minutes
24 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
63 Login storm and steady state for standard users (LoginVSI
Medium) Login VSI was programmed to start 800 virtual desktops over a period of about 60 minutes after pre-
booting the virtual desktops The peak IOPS during the login storm observed by the vSphere servers
hosting the desktops was about 6500 IOPS (8ndash10 IOPS a VM)
In a standard user environment login storms generate significantly more write IOPS than a boot storm or
steady state because of multiple factors such as
User profile activity
Starting operating system services on the desktop
First start of applications
After a virtual desktop has achieved a steady state after user login the Windows 7 OS has cached
applications in memory and does not need to access storage each time the application is started This
leads to lesser IOPS during the steady state Figure 7 here shows the various IO characteristics during the
login storm and steady state of these tests
25 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 7 IOPS and Cache Hit for the standard user test
On the Fluid Cache layer the maximum IOPS reached 6500 with cache-hit reaching 100 percent and
read-hit around 95 percent As shown in the Figure 8 here the throughput peaked at 98 MBps with a low
latency of less than 2 msec
26 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 8 Throughput and Latency for the standard user test
631 Server host performance During the login storm and steady state of the test the vSphere host CPU memory network and storage
performance were measured on all the servers that hosted the virtual desktops The performance of one
such vSphere server is given here The other vSphere servers had similar performance characteristics
Statistics for the vSphere hosts were captured by using VMware vCenter Server The figures here show the
CPU memory and network utilization for boot storm login storm and steady state of one of the vSphere
servers hosting the virtual desktops The results shown here are for a test run with 800 no standard user
desktops in the desktop pool
27 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 9 Average CPU performance per core on one vSphere host during login storm and steady state
Figure 10 Disk space usage during login storm and steady state
0
10
20
30
40
50
60
70
80
90
100
1020 1045 1110 1135 1200 1225
Per
cen
t
Time
CPU Performance
0
50
100
150
200
250
300
1020 1040 1100 1120 1140 1200 1220
GB
Time
Memory Performance
Granted Swap used Shared common
28 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 11 Overall network performance during login storm and steady state
Figure 12 Storage adapter performance during login storm and steady state
0
10000
20000
30000
40000
50000
60000
70000
1020 1045 1110 1135 1200 1225
kBp
s
Time
Network Performance
0
05
1
15
2
25
1020 1045 1110 1135 1200 1225
mSe
c
Time
Storage adaptor performance
29 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
The key observations from the statistics were
CPU utilization was less than the 85 percent threshold throughout the test
Active disk space usage was about 80 percent during the boost storm and about 60 percent
during login storm and steady state There was minimal-or no memory ballooning observed
Network utilization was about 45 percent which included all the networks such as iSCSI SAN VDI
LAN Management LAN and vMotion LAN
Average read- and write latencies at the storage adapter level were very close to the observed
latencies in Fluid Cache 2 msec
632 Monitoring user experience Figure 13 here shows the response time as experienced by each user as calculated by Login VSI The graph
clearly shows that the VSImax (Dynamic) value has not been reached and there were non-responsive or
inactive sessions This means that the array is capable of supporting the 1000 desktops and all users have
acceptable response times for applications that the user is has started
Figure 13 Login VSI user experience monitoring for 800 standard user desktops
30 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
633 Standard user test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SANndashbased VDI solution is able to host 800 virtual desktops and support
a standard user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only operations and
less than 2 percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to handle this login storm easily with low latency mdash it delivered the required 6500 IOPS with less
than 2 milliseconds of write latency with a 99 percent write VDI IO workload
64 Login storm and steady state with high IOPS (LoginVSI Medium +
Iometer) As mentioned earlier Iometer was used in desktop VMs alongside the Login VSI Medium workload to
simulate high IOPS type of VDI environment To mimic actual VDI workload profile the following Iometer
profile was used
20 KB block size 80 percent write 75 percent random with 25 msec burst delay
Figure 14 here shows the various IO characteristics during the login storm and steady state of these tests
Figure 14 IOPS and Cache Hit for the high IOPS test
On the Fluid Cache layer the maximum IOPS reached was approximately 72000 (or 90 IOPSVM) with
cache write-hit 100 percent and read-hit around 95 percent As shown in the Figure 15 the throughput
peaked at greater than 900 MBps with a peak latency of approximately 75 msec
31 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 15 Throughput and Latency for the high IOPS test
32 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
641 Server host performance Similar to the standard user test statistics for the vSphere hosts were captured by using VMware vCenter
Server during the high IOPS (heavy user) test also There are no significant differences in CPU disk space
and network utilization between standard users and heavy users The storage adapter latency is also
showing similar on hosts and observed on Fluid Cache
642 User experience monitoring Figure 16 here shows the response time as experienced by each user as calculated by Login VSI for the
heavy user test The graph shows that the VSImax (Dynamic) value was 796 indicating that the solution is
capable of supporting the 800 user high IOPS desktops with 90 IOPSVM
Figure 16 Login VSI user experience monitoring for 800 user high IOPS desktops
33 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
643 High IOPS (heavy user) test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SAN based VDI solution is able to host 800 virtual desktops and support a
high user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only and less than 2
percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to easily handle this login storm with low latency Subsequently it was able to handle 72000 IOPS
at high IOPS steady state with 90 IOPSVM with a maximum of 75 msec latency
34 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
7 Best practices This section provides the best practices derived from the testing and analysis in Section 6
71 Virtual Desktop Infrastructure This section provides best practices for the implementation of VDI using Dell Fluid Cache for SAN
711 Implement roaming profiles and folder redirection Dell recommends that all users in the VDI environment be configured with roaming profiles and folder
redirection This preserves user profiles and user data across boots while using non-persistent virtual
desktops
Also Dell recommends to use a high performance file service to provide the profile and folder redirection
A separate array may be used to host these volumes for best performance
712 Boot and login storm considerations Section 62 demonstrated the Fluid Cache for SAN performance under boot storm To avoid any potential
IO bursts because of boot storm and degraded user experience and performances Dell recommends that
all or portion of desktops be prebooted Connection brokers such as VMware Horizon View provide the
functionality to configure number of standby desktops
713 Windows 7 master image for desktop VMs Dell recommends that the operating system be customized in order to provide the best performance in a
VDI environment This includes disabling some services which may not be required This can improve
performance for the end user VMware has a specific set of recommendations and settings for Windows 7
and Windows 8 that allow for faster logins quicker screen refreshes and generally better performance
The VMware recommendations for Windows 7 and Windows 8 image optimization can be found here
httpwwwvmwarecomresourcestechresources10157
714 VDI Management infrastructure recommendations Dell recommends to have redundancy and load balancing for all VDI management services in the case of
VMware Horizon View solution as tested here the vSphere Server VMware Horizon View Servers and SQL
Servers Ideally these should be running on clustered hosts with VMware vSphere DRS (distributed
resource scheduler) and HA (high availability) enabled
72 Server host The vSphere servers hosting the infrastructure service providers and the virtual desktops are
recommended to be configured as follows
35 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Follow VMware and Dell best practices for installing and configuring vSphere
Separate virtual switches to segregate iSCSI SAN traffic VDI traffic vMotion traffic and Management
network traffic
Each network path must be assigned to a minimum of two physical NICs for high availability
VMware Knowledge Base article about best practices for installing vSphere 55
httpkbvmwarecomkb2052329
73 Network layer Dell recommends that at least two physical NICs on each vSphere server be dedicated to the VDI network
Use VLANs to segregate different types of network traffic on the same physical network In this case Dell
recommends to separate the infrastructure vMotion and VDI LAN traffic in to separate VLANs
Do not use VLANs to segregate iSCSI SAN and Fluide Cache traffic It is required that SAN and Cache traffic
be on separate dedicated physical network to provide the best performance
Virtual switches in vSphere have a default limit of 120 ports If the number of virtual desktops on each host
exceeds the available ports vSwitch properties should be changed to support the required number of
virtual desktops This change requires a restart of the host vSphere server
On iSCSI SAN switches Spanning tree must be disabled on switch ports connected to end devices for
server and storage ports The PortFast setting must be enabled in the switch configuration for these ports
Jumbo frames and Flow control (if the NICs support it) should be enabled for all components of the iSCSI
network
More information about configuring Dell Networking switches for use with Dell Storage iSCSI SANs is
available here
httpencommunitydellcomtechcenterstoragewwiki4250switch-configuration-guides-by-sisaspx
74 Storage The Dell SC storage arrays combined with Fluid Cache is an excellent platform for providing cost-effective
performance in VDI environments
Fluid Cache for SAN extends the power of Compellent intelligent data placement from the SAN to the
server By providing a single infrastructure for data at both high- and low ends of the performance
spectrum Fluid Cache for SAN with Storage Center 65 array software eliminates the tradeoffs between
server performance and full-featured SAN benefits such as reliability manageability and data protection
Dell recommends to have separate volumes for base image and virtual desktops This enables better
manageability of the volumes easier performance monitoring and allows easy future growth
Dell recommends to use a separate high performance file service to provide file shares for roaming
profiles and user shares
36 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
8 Conclusion The technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed by using a Horizon View VDI platform leveraging Dell Fluid Cache for SAN The storage IO
characteristics under various VDI workload scenarios (boot storm login storm and steady state) along
with performance characteristics throughout the VDI stack (for example vSphere server performance and
user experience) demonstrate the optimal configuration of the infrastructure used for this VDI
deployment For more information about Fluid Cache contact your Dell account manager
37 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
A Horizon view solution configuration
Table 7 Hardware components
Hardware components Description
Virtual Desktops 4 timesDell PowerEdge R720 Servers (Fluid Cache Providers)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
2times350 GB Dell Express Flash PCIe SSDs
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
4 x Dell PowerEdge R720 Servers (Fluid Cache Clients)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55 U2 on all R720 servers Windows 7 (64 Bit) VMs
Infrastructure Servers 2 x Dell PowerEdge R720 servers
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
96 GB RAM
2times300 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55U2 on all R720 servers VMs are loaded with Microsoft Windows 2008 R2
Active Directory
VMware Horizon View 60 Server 1
VMware Horizon View 60 Server 2
VMware vCenter Server 55 update 2
VMware Horizon View Composer
SQL Server
File Server
Login VSI Launchers 8 x Dell PowerEdge M610 servers
2timesIntelreg Xeonreg E-5503 200 GHz Processors
16 GB RAM
4times146 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57711 10GbE NIC
ESXi 51 installed on all R810 servers VMs are loaded with Microsoft Windows 7 64bit Each VM supports up to 30 Login VSI launcher sessions
38 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Network Management VDI LAN
1timesDell Force10 S55 1Gb Ethernet Switch
iSCSI SAN
1timesDell Force10 S4810 10Gb Ethernet Switch
Cache network
1timesDell Force10 S4810 10Gb Ethernet Switch
One Force10 S4810 switch might suffice for all the cache iSCSI SAN VDI LAN and management traffic
Storage 2timesDell Compellent SC8000 controllers 4times6Gb SAS 4-port PCI-E Full-height cards for back-end connectivity 2times10Gb iSCSI 2 port PCI-E Low-profile IO cards for front end connectivity 1timesDell Compellent SC200 disk enclosures 12times4TB NL-SAS 6Gb 72K 35rdquo drives
User Data Infrastructure VMs Virtual Desktops
Performance Monitoring
Dell Compellent Enterprise Manager Dell Fluid Cache for SAN performance monitoring tool () vCenter Performance monitoring Liquidware Stratusphere UX
Performance monitoring on Compellent arrays Fluid Cache performance monitoring Performance monitoring and capture at the ESXi host User experience monitoring on the virtual desktop
39 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 8 Software components
Software components Description Version
Dell Fluid Cache for SAN 20
Dell Compellent Storage Center 64
Dell Compellent Enterprise Manager 64
VMware Horizon View Server 60
VMware Horizon View Composer 60
VMware Horizon View Agent 60
VMware Horizon View Client 64-bit 60
VMware ESXi Hypervisor 55 U2
VMware vCenter Server 55 U2
Microsoft SQL Server 2008R2 Enterprise x64 105016001
Client VM OS Microsoft Windows 7 Enterprise x64 SP1
Management VM OS Microsoft Windows Server 2008 Enterprise R2 x64 SP1
Microsoft Office MS office 2010 Standard Service Pack 1
Login VSI Version 40
Iometer 20060727
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
17 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 4 Dell Storage PS4210XS layout for volumes hosting virtual desktops
Volume name Size Purpose
View-Replicas1 and 2 100 GB each Storage for base image for VDI deployment
VDI-Images1 through 8 500 GB each Storage for VDI VMs in VDI Cluster Each volume hosted 100 desktops
44 vSphere host network configuration VMware vSphere 55 hypervisor was installed on all servers The network configuration on each of those
hosts is described here Each vSphere host was configured with five virtual switches vSwitch0 vSwitch1
vSwitch2 vSwitch3 and vSwitch4 to separate different types of traffic on the system
Table 5 vSwitch configuration in vSphere hosts
vSwitch Description
vSwitch0 Management Network
vSwitch1 and vSwitch2 iSCSI SAN
vSwitch3 Fluid Cache VLAN
vSwitch4 VDI LAN
For additional information about individual vSwitch configuration refer to Appendix B in the Dell technical
white paper
45 Horizon view configuration Horizon View 60 was installed by using the documentation provided by VMware
Horizon View 601 installation documentation
httpswwwvmwarecomsupportpubsview_pubshtml
Table 6 Specific configuration used in the tests
Purpose Count Type Memory CPU
Horizon View Connection Servers
2 VM 16 GB 8nos
View Composer Server 1 VM 8 GB 8nos
18 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
46 Windows 7 VM configuration Following the guidelines from VMware and Login VSI the Windows 7 base image was generated based on
a generic base VM with the following properties
VMware Virtual Hardware version 8
Two virtual CPU
3 GB RAM with 15GB reserved
25 GB virtual hard drive
One virtual NIC connected to the VDI network
Windows 7 64-bit OS
Also the base image was customized by using the VMware Horizon with View Optimization Guide for
Windows 7 and Windows 8 available at this location httpwwwvmwarecomfilespdfVMware-View-
OptimizationGuideWindows7-ENpdf
19 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
5 Horizon view test methodology This section outlines the test objectives along with the test tools and criteria used to determine the
optimal virtual desktop density and best practices for deploying Horizon View on Dell Fluid Cache for SAN
for high IOPS type VDI environment
51 Test objectives As noted in Section 11 the test objectives were
Develop an optimal end-to-end infrastructure design for a Horizon View and vSpherendashbased high
user type of VDI solution deployed by using the Fluid Cache Compellent storage PowerEdge
servers and Dell Networking switches
Determine the performance at every layer of the VDI solution stack under high IOPS workload For
example desktops generating 80ndash90 IOPSVM at steady state
Determine the performance impact of peak IO activity such as boot and login storms
52 Test tools All tests were conducted by using Login VSI 40 as the workload generator and user experience analyzer
tool Login VSI is a benchmarking tool to measure the performance and scalability of centralized desktop
environments such as Server Based Computing (SBC) and VDI
Note More information can be found at the Login VSI website httpwwwloginvsicom
In addition to Login VSI Iometer is used in desktop VMs to simulate high IOPS conditions Iometer is
invoked in desktop VMs by using custom scripting of Login VSI workloads
Note More information can be found at the Iometer project website httpwwwiometerorg
521 Load generation First the ldquoMediumrdquo workload from Login VSI was used to simulate the standard user workload The
characteristics of the Medium workload are
Up to five applications are started simultaneously
Applications include Microsoft Internet Explorer Microsoft Word Microsoft Excel Microsoft
PowerPoint PDF reader 7-Zip compression software Movie player and FreeMind
After a session is started the medium workload repeats approximately after every 48 minutes
During a loop the response time is measured after every 3ndash4 minutes
Idle time is about two minutes in each 48-minute loop
Type rate is approximately 160 milliseconds per character
After the test by using Login VSI Medium was complete tests were rerun with Login VSI Medium and
Iometer in desktop VMs to simulate high IOPS VDI workload While the Login VSI Medium generates 8ndash10
20 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
IOPSVM the latter method was able to generate 80ndash90 IOPSVM For these tests each VM in the Horizon
view pool is created with standard LoginVSI contents and applications Also Iometer is installed on each
VM After the user logs in a customized logon script starts the Iometer with required IO specification (icf
file)
522 Monitoring tools The following monitoring tools were used
Dell Compellent Enterprise Manager for monitoring Fluid Cache and Compellent SC8000 storage
array performance
VMware vCenter statistics for vSphere performance
Login VSI Analyzer for end user performance statistics
Detailed performance metrics were captured from the storage arrays hypervisors virtual desktops and
the load generators during the tests
53 Test criteria The primary focus of the tests is to validate the 800 desktop high IOPS type of VDI architecture with
acceptable user experience by using Fluid Cache for SAN VDI configurations involve many components at
different layers ndash application hypervisor server network and storage As a result multiple metrics need to
be captured at different layers to ensure that the environment is healthy and performing optimally and
appropriately for all users
The specific test criteria are described in the following sections
531 Storage capacity and IO latency The typical industry standard latency limit for storage disk IO is 10 milliseconds Maintaining this limit
ensures good user application response times when there are no other bottlenecks at the infrastructure
layer In addition Dell recommends to maintain a 10 percent spare disk space on the storage array for
optimal performance
532 System utilization at the hypervisor Even though the primary focus of these tests was storage characterization additional metrics at the
hypervisor infrastructure layer were defined to ensure solution consistency These were
CPU utilization on any vSphere server must not exceed 85 percent
Minimal memory ballooning on the VMs
Total network bandwidth utilization must not exceed 90 percent on any one link
TCPIP storage network retransmissions should be less than 05 percent
21 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
533 Virtual desktop user experience Login VSI Analyzer was also used to gather metrics on the user experience at the virtual desktop layer to
ensure that all the desktops had acceptable levels of application performance Login VSI uses the VSImax
parameter to determine the maximum number of sessions that can be obtained from a deployed solution
The calculation methodology used in VSImax is available here
httpwwwloginvsicomdocumentationindexphptitle=Analyzing_Results
534 Test configuration A single virtual desktop pool was configured by using the VMware Horizon View Administrator interface
Each pool was built from a Windows 7 base image The Windows 7 configuration information is available
in Section 46
Desktop pool properties
Automatic Desktop Pool
Users are assigned using Floating assignments
View Storage Accelerator is enabled for all hosts with a refresh period of seven days
800 desktops were deployed across eight hosts (100 desktops a host)
Replica images were stored on a separate volume
22 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
6 Test results and analysis This section presents the results from the different Horizon View VDI characterization tests and the key
findings from each test The testing was focused on the high IOPS workload profile
61 Test scenarios The following tests were conducted to gather results and analysis on the solution stack
1 Boot storm Boot storms represent the worst-case scenario where many virtual desktops are
turned on at the same time and they all contend for the system resources simultaneously This test
was used to evaluate if the storage array hosting the desktops was capable of handling huge
variation in storage IO without causing significant impact on other services
2 Login storm Login storms also represent a high IOPS situation where many users are logging in to
their virtual desktops at the beginning of a workday or a shift In this test all the desktops were
pre-booted and left in an idle state for more than 20 minutes to let their IO settle before running
the Login VSI Medium workload to simulate users logging in to their virtual desktops
3 Steady state workload for standard users with normal IOPS After the login storm for the previous
test was completed the Login VSI Medium workload was allowed to run for at least one hour to
simulate the real-world scenario of users performing their daily tasks The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
4 Steady state workload for users with high IOPS The previous test was repeated with the Login
VSI Medium workload and Iometer scripts in desktop VMs as described in Section 521 to simulate
real-world heavy users performing their daily tasks with high IOPS The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
The following sections provide results from the boot storm login storm and steady state testing for the
Fluid Cache for SAN based VDI solution
23 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
62 Boot storm IO To simulate a boot storm the virtual desktops were reset simultaneously from the VMware vSphere client
Figure 6 shows the IO pattern on the Fluid Cache for the boot storm
Figure 6 SAN HQ data showing boot storm performance with Fluid Cache array
With 800 desktops the boot storm generated about 115000 total IOPS with a majority of them being
write operations All desktops were available for use in less than four minutes
24 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
63 Login storm and steady state for standard users (LoginVSI
Medium) Login VSI was programmed to start 800 virtual desktops over a period of about 60 minutes after pre-
booting the virtual desktops The peak IOPS during the login storm observed by the vSphere servers
hosting the desktops was about 6500 IOPS (8ndash10 IOPS a VM)
In a standard user environment login storms generate significantly more write IOPS than a boot storm or
steady state because of multiple factors such as
User profile activity
Starting operating system services on the desktop
First start of applications
After a virtual desktop has achieved a steady state after user login the Windows 7 OS has cached
applications in memory and does not need to access storage each time the application is started This
leads to lesser IOPS during the steady state Figure 7 here shows the various IO characteristics during the
login storm and steady state of these tests
25 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 7 IOPS and Cache Hit for the standard user test
On the Fluid Cache layer the maximum IOPS reached 6500 with cache-hit reaching 100 percent and
read-hit around 95 percent As shown in the Figure 8 here the throughput peaked at 98 MBps with a low
latency of less than 2 msec
26 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 8 Throughput and Latency for the standard user test
631 Server host performance During the login storm and steady state of the test the vSphere host CPU memory network and storage
performance were measured on all the servers that hosted the virtual desktops The performance of one
such vSphere server is given here The other vSphere servers had similar performance characteristics
Statistics for the vSphere hosts were captured by using VMware vCenter Server The figures here show the
CPU memory and network utilization for boot storm login storm and steady state of one of the vSphere
servers hosting the virtual desktops The results shown here are for a test run with 800 no standard user
desktops in the desktop pool
27 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 9 Average CPU performance per core on one vSphere host during login storm and steady state
Figure 10 Disk space usage during login storm and steady state
0
10
20
30
40
50
60
70
80
90
100
1020 1045 1110 1135 1200 1225
Per
cen
t
Time
CPU Performance
0
50
100
150
200
250
300
1020 1040 1100 1120 1140 1200 1220
GB
Time
Memory Performance
Granted Swap used Shared common
28 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 11 Overall network performance during login storm and steady state
Figure 12 Storage adapter performance during login storm and steady state
0
10000
20000
30000
40000
50000
60000
70000
1020 1045 1110 1135 1200 1225
kBp
s
Time
Network Performance
0
05
1
15
2
25
1020 1045 1110 1135 1200 1225
mSe
c
Time
Storage adaptor performance
29 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
The key observations from the statistics were
CPU utilization was less than the 85 percent threshold throughout the test
Active disk space usage was about 80 percent during the boost storm and about 60 percent
during login storm and steady state There was minimal-or no memory ballooning observed
Network utilization was about 45 percent which included all the networks such as iSCSI SAN VDI
LAN Management LAN and vMotion LAN
Average read- and write latencies at the storage adapter level were very close to the observed
latencies in Fluid Cache 2 msec
632 Monitoring user experience Figure 13 here shows the response time as experienced by each user as calculated by Login VSI The graph
clearly shows that the VSImax (Dynamic) value has not been reached and there were non-responsive or
inactive sessions This means that the array is capable of supporting the 1000 desktops and all users have
acceptable response times for applications that the user is has started
Figure 13 Login VSI user experience monitoring for 800 standard user desktops
30 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
633 Standard user test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SANndashbased VDI solution is able to host 800 virtual desktops and support
a standard user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only operations and
less than 2 percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to handle this login storm easily with low latency mdash it delivered the required 6500 IOPS with less
than 2 milliseconds of write latency with a 99 percent write VDI IO workload
64 Login storm and steady state with high IOPS (LoginVSI Medium +
Iometer) As mentioned earlier Iometer was used in desktop VMs alongside the Login VSI Medium workload to
simulate high IOPS type of VDI environment To mimic actual VDI workload profile the following Iometer
profile was used
20 KB block size 80 percent write 75 percent random with 25 msec burst delay
Figure 14 here shows the various IO characteristics during the login storm and steady state of these tests
Figure 14 IOPS and Cache Hit for the high IOPS test
On the Fluid Cache layer the maximum IOPS reached was approximately 72000 (or 90 IOPSVM) with
cache write-hit 100 percent and read-hit around 95 percent As shown in the Figure 15 the throughput
peaked at greater than 900 MBps with a peak latency of approximately 75 msec
31 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 15 Throughput and Latency for the high IOPS test
32 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
641 Server host performance Similar to the standard user test statistics for the vSphere hosts were captured by using VMware vCenter
Server during the high IOPS (heavy user) test also There are no significant differences in CPU disk space
and network utilization between standard users and heavy users The storage adapter latency is also
showing similar on hosts and observed on Fluid Cache
642 User experience monitoring Figure 16 here shows the response time as experienced by each user as calculated by Login VSI for the
heavy user test The graph shows that the VSImax (Dynamic) value was 796 indicating that the solution is
capable of supporting the 800 user high IOPS desktops with 90 IOPSVM
Figure 16 Login VSI user experience monitoring for 800 user high IOPS desktops
33 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
643 High IOPS (heavy user) test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SAN based VDI solution is able to host 800 virtual desktops and support a
high user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only and less than 2
percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to easily handle this login storm with low latency Subsequently it was able to handle 72000 IOPS
at high IOPS steady state with 90 IOPSVM with a maximum of 75 msec latency
34 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
7 Best practices This section provides the best practices derived from the testing and analysis in Section 6
71 Virtual Desktop Infrastructure This section provides best practices for the implementation of VDI using Dell Fluid Cache for SAN
711 Implement roaming profiles and folder redirection Dell recommends that all users in the VDI environment be configured with roaming profiles and folder
redirection This preserves user profiles and user data across boots while using non-persistent virtual
desktops
Also Dell recommends to use a high performance file service to provide the profile and folder redirection
A separate array may be used to host these volumes for best performance
712 Boot and login storm considerations Section 62 demonstrated the Fluid Cache for SAN performance under boot storm To avoid any potential
IO bursts because of boot storm and degraded user experience and performances Dell recommends that
all or portion of desktops be prebooted Connection brokers such as VMware Horizon View provide the
functionality to configure number of standby desktops
713 Windows 7 master image for desktop VMs Dell recommends that the operating system be customized in order to provide the best performance in a
VDI environment This includes disabling some services which may not be required This can improve
performance for the end user VMware has a specific set of recommendations and settings for Windows 7
and Windows 8 that allow for faster logins quicker screen refreshes and generally better performance
The VMware recommendations for Windows 7 and Windows 8 image optimization can be found here
httpwwwvmwarecomresourcestechresources10157
714 VDI Management infrastructure recommendations Dell recommends to have redundancy and load balancing for all VDI management services in the case of
VMware Horizon View solution as tested here the vSphere Server VMware Horizon View Servers and SQL
Servers Ideally these should be running on clustered hosts with VMware vSphere DRS (distributed
resource scheduler) and HA (high availability) enabled
72 Server host The vSphere servers hosting the infrastructure service providers and the virtual desktops are
recommended to be configured as follows
35 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Follow VMware and Dell best practices for installing and configuring vSphere
Separate virtual switches to segregate iSCSI SAN traffic VDI traffic vMotion traffic and Management
network traffic
Each network path must be assigned to a minimum of two physical NICs for high availability
VMware Knowledge Base article about best practices for installing vSphere 55
httpkbvmwarecomkb2052329
73 Network layer Dell recommends that at least two physical NICs on each vSphere server be dedicated to the VDI network
Use VLANs to segregate different types of network traffic on the same physical network In this case Dell
recommends to separate the infrastructure vMotion and VDI LAN traffic in to separate VLANs
Do not use VLANs to segregate iSCSI SAN and Fluide Cache traffic It is required that SAN and Cache traffic
be on separate dedicated physical network to provide the best performance
Virtual switches in vSphere have a default limit of 120 ports If the number of virtual desktops on each host
exceeds the available ports vSwitch properties should be changed to support the required number of
virtual desktops This change requires a restart of the host vSphere server
On iSCSI SAN switches Spanning tree must be disabled on switch ports connected to end devices for
server and storage ports The PortFast setting must be enabled in the switch configuration for these ports
Jumbo frames and Flow control (if the NICs support it) should be enabled for all components of the iSCSI
network
More information about configuring Dell Networking switches for use with Dell Storage iSCSI SANs is
available here
httpencommunitydellcomtechcenterstoragewwiki4250switch-configuration-guides-by-sisaspx
74 Storage The Dell SC storage arrays combined with Fluid Cache is an excellent platform for providing cost-effective
performance in VDI environments
Fluid Cache for SAN extends the power of Compellent intelligent data placement from the SAN to the
server By providing a single infrastructure for data at both high- and low ends of the performance
spectrum Fluid Cache for SAN with Storage Center 65 array software eliminates the tradeoffs between
server performance and full-featured SAN benefits such as reliability manageability and data protection
Dell recommends to have separate volumes for base image and virtual desktops This enables better
manageability of the volumes easier performance monitoring and allows easy future growth
Dell recommends to use a separate high performance file service to provide file shares for roaming
profiles and user shares
36 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
8 Conclusion The technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed by using a Horizon View VDI platform leveraging Dell Fluid Cache for SAN The storage IO
characteristics under various VDI workload scenarios (boot storm login storm and steady state) along
with performance characteristics throughout the VDI stack (for example vSphere server performance and
user experience) demonstrate the optimal configuration of the infrastructure used for this VDI
deployment For more information about Fluid Cache contact your Dell account manager
37 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
A Horizon view solution configuration
Table 7 Hardware components
Hardware components Description
Virtual Desktops 4 timesDell PowerEdge R720 Servers (Fluid Cache Providers)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
2times350 GB Dell Express Flash PCIe SSDs
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
4 x Dell PowerEdge R720 Servers (Fluid Cache Clients)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55 U2 on all R720 servers Windows 7 (64 Bit) VMs
Infrastructure Servers 2 x Dell PowerEdge R720 servers
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
96 GB RAM
2times300 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55U2 on all R720 servers VMs are loaded with Microsoft Windows 2008 R2
Active Directory
VMware Horizon View 60 Server 1
VMware Horizon View 60 Server 2
VMware vCenter Server 55 update 2
VMware Horizon View Composer
SQL Server
File Server
Login VSI Launchers 8 x Dell PowerEdge M610 servers
2timesIntelreg Xeonreg E-5503 200 GHz Processors
16 GB RAM
4times146 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57711 10GbE NIC
ESXi 51 installed on all R810 servers VMs are loaded with Microsoft Windows 7 64bit Each VM supports up to 30 Login VSI launcher sessions
38 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Network Management VDI LAN
1timesDell Force10 S55 1Gb Ethernet Switch
iSCSI SAN
1timesDell Force10 S4810 10Gb Ethernet Switch
Cache network
1timesDell Force10 S4810 10Gb Ethernet Switch
One Force10 S4810 switch might suffice for all the cache iSCSI SAN VDI LAN and management traffic
Storage 2timesDell Compellent SC8000 controllers 4times6Gb SAS 4-port PCI-E Full-height cards for back-end connectivity 2times10Gb iSCSI 2 port PCI-E Low-profile IO cards for front end connectivity 1timesDell Compellent SC200 disk enclosures 12times4TB NL-SAS 6Gb 72K 35rdquo drives
User Data Infrastructure VMs Virtual Desktops
Performance Monitoring
Dell Compellent Enterprise Manager Dell Fluid Cache for SAN performance monitoring tool () vCenter Performance monitoring Liquidware Stratusphere UX
Performance monitoring on Compellent arrays Fluid Cache performance monitoring Performance monitoring and capture at the ESXi host User experience monitoring on the virtual desktop
39 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 8 Software components
Software components Description Version
Dell Fluid Cache for SAN 20
Dell Compellent Storage Center 64
Dell Compellent Enterprise Manager 64
VMware Horizon View Server 60
VMware Horizon View Composer 60
VMware Horizon View Agent 60
VMware Horizon View Client 64-bit 60
VMware ESXi Hypervisor 55 U2
VMware vCenter Server 55 U2
Microsoft SQL Server 2008R2 Enterprise x64 105016001
Client VM OS Microsoft Windows 7 Enterprise x64 SP1
Management VM OS Microsoft Windows Server 2008 Enterprise R2 x64 SP1
Microsoft Office MS office 2010 Standard Service Pack 1
Login VSI Version 40
Iometer 20060727
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
18 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
46 Windows 7 VM configuration Following the guidelines from VMware and Login VSI the Windows 7 base image was generated based on
a generic base VM with the following properties
VMware Virtual Hardware version 8
Two virtual CPU
3 GB RAM with 15GB reserved
25 GB virtual hard drive
One virtual NIC connected to the VDI network
Windows 7 64-bit OS
Also the base image was customized by using the VMware Horizon with View Optimization Guide for
Windows 7 and Windows 8 available at this location httpwwwvmwarecomfilespdfVMware-View-
OptimizationGuideWindows7-ENpdf
19 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
5 Horizon view test methodology This section outlines the test objectives along with the test tools and criteria used to determine the
optimal virtual desktop density and best practices for deploying Horizon View on Dell Fluid Cache for SAN
for high IOPS type VDI environment
51 Test objectives As noted in Section 11 the test objectives were
Develop an optimal end-to-end infrastructure design for a Horizon View and vSpherendashbased high
user type of VDI solution deployed by using the Fluid Cache Compellent storage PowerEdge
servers and Dell Networking switches
Determine the performance at every layer of the VDI solution stack under high IOPS workload For
example desktops generating 80ndash90 IOPSVM at steady state
Determine the performance impact of peak IO activity such as boot and login storms
52 Test tools All tests were conducted by using Login VSI 40 as the workload generator and user experience analyzer
tool Login VSI is a benchmarking tool to measure the performance and scalability of centralized desktop
environments such as Server Based Computing (SBC) and VDI
Note More information can be found at the Login VSI website httpwwwloginvsicom
In addition to Login VSI Iometer is used in desktop VMs to simulate high IOPS conditions Iometer is
invoked in desktop VMs by using custom scripting of Login VSI workloads
Note More information can be found at the Iometer project website httpwwwiometerorg
521 Load generation First the ldquoMediumrdquo workload from Login VSI was used to simulate the standard user workload The
characteristics of the Medium workload are
Up to five applications are started simultaneously
Applications include Microsoft Internet Explorer Microsoft Word Microsoft Excel Microsoft
PowerPoint PDF reader 7-Zip compression software Movie player and FreeMind
After a session is started the medium workload repeats approximately after every 48 minutes
During a loop the response time is measured after every 3ndash4 minutes
Idle time is about two minutes in each 48-minute loop
Type rate is approximately 160 milliseconds per character
After the test by using Login VSI Medium was complete tests were rerun with Login VSI Medium and
Iometer in desktop VMs to simulate high IOPS VDI workload While the Login VSI Medium generates 8ndash10
20 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
IOPSVM the latter method was able to generate 80ndash90 IOPSVM For these tests each VM in the Horizon
view pool is created with standard LoginVSI contents and applications Also Iometer is installed on each
VM After the user logs in a customized logon script starts the Iometer with required IO specification (icf
file)
522 Monitoring tools The following monitoring tools were used
Dell Compellent Enterprise Manager for monitoring Fluid Cache and Compellent SC8000 storage
array performance
VMware vCenter statistics for vSphere performance
Login VSI Analyzer for end user performance statistics
Detailed performance metrics were captured from the storage arrays hypervisors virtual desktops and
the load generators during the tests
53 Test criteria The primary focus of the tests is to validate the 800 desktop high IOPS type of VDI architecture with
acceptable user experience by using Fluid Cache for SAN VDI configurations involve many components at
different layers ndash application hypervisor server network and storage As a result multiple metrics need to
be captured at different layers to ensure that the environment is healthy and performing optimally and
appropriately for all users
The specific test criteria are described in the following sections
531 Storage capacity and IO latency The typical industry standard latency limit for storage disk IO is 10 milliseconds Maintaining this limit
ensures good user application response times when there are no other bottlenecks at the infrastructure
layer In addition Dell recommends to maintain a 10 percent spare disk space on the storage array for
optimal performance
532 System utilization at the hypervisor Even though the primary focus of these tests was storage characterization additional metrics at the
hypervisor infrastructure layer were defined to ensure solution consistency These were
CPU utilization on any vSphere server must not exceed 85 percent
Minimal memory ballooning on the VMs
Total network bandwidth utilization must not exceed 90 percent on any one link
TCPIP storage network retransmissions should be less than 05 percent
21 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
533 Virtual desktop user experience Login VSI Analyzer was also used to gather metrics on the user experience at the virtual desktop layer to
ensure that all the desktops had acceptable levels of application performance Login VSI uses the VSImax
parameter to determine the maximum number of sessions that can be obtained from a deployed solution
The calculation methodology used in VSImax is available here
httpwwwloginvsicomdocumentationindexphptitle=Analyzing_Results
534 Test configuration A single virtual desktop pool was configured by using the VMware Horizon View Administrator interface
Each pool was built from a Windows 7 base image The Windows 7 configuration information is available
in Section 46
Desktop pool properties
Automatic Desktop Pool
Users are assigned using Floating assignments
View Storage Accelerator is enabled for all hosts with a refresh period of seven days
800 desktops were deployed across eight hosts (100 desktops a host)
Replica images were stored on a separate volume
22 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
6 Test results and analysis This section presents the results from the different Horizon View VDI characterization tests and the key
findings from each test The testing was focused on the high IOPS workload profile
61 Test scenarios The following tests were conducted to gather results and analysis on the solution stack
1 Boot storm Boot storms represent the worst-case scenario where many virtual desktops are
turned on at the same time and they all contend for the system resources simultaneously This test
was used to evaluate if the storage array hosting the desktops was capable of handling huge
variation in storage IO without causing significant impact on other services
2 Login storm Login storms also represent a high IOPS situation where many users are logging in to
their virtual desktops at the beginning of a workday or a shift In this test all the desktops were
pre-booted and left in an idle state for more than 20 minutes to let their IO settle before running
the Login VSI Medium workload to simulate users logging in to their virtual desktops
3 Steady state workload for standard users with normal IOPS After the login storm for the previous
test was completed the Login VSI Medium workload was allowed to run for at least one hour to
simulate the real-world scenario of users performing their daily tasks The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
4 Steady state workload for users with high IOPS The previous test was repeated with the Login
VSI Medium workload and Iometer scripts in desktop VMs as described in Section 521 to simulate
real-world heavy users performing their daily tasks with high IOPS The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
The following sections provide results from the boot storm login storm and steady state testing for the
Fluid Cache for SAN based VDI solution
23 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
62 Boot storm IO To simulate a boot storm the virtual desktops were reset simultaneously from the VMware vSphere client
Figure 6 shows the IO pattern on the Fluid Cache for the boot storm
Figure 6 SAN HQ data showing boot storm performance with Fluid Cache array
With 800 desktops the boot storm generated about 115000 total IOPS with a majority of them being
write operations All desktops were available for use in less than four minutes
24 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
63 Login storm and steady state for standard users (LoginVSI
Medium) Login VSI was programmed to start 800 virtual desktops over a period of about 60 minutes after pre-
booting the virtual desktops The peak IOPS during the login storm observed by the vSphere servers
hosting the desktops was about 6500 IOPS (8ndash10 IOPS a VM)
In a standard user environment login storms generate significantly more write IOPS than a boot storm or
steady state because of multiple factors such as
User profile activity
Starting operating system services on the desktop
First start of applications
After a virtual desktop has achieved a steady state after user login the Windows 7 OS has cached
applications in memory and does not need to access storage each time the application is started This
leads to lesser IOPS during the steady state Figure 7 here shows the various IO characteristics during the
login storm and steady state of these tests
25 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 7 IOPS and Cache Hit for the standard user test
On the Fluid Cache layer the maximum IOPS reached 6500 with cache-hit reaching 100 percent and
read-hit around 95 percent As shown in the Figure 8 here the throughput peaked at 98 MBps with a low
latency of less than 2 msec
26 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 8 Throughput and Latency for the standard user test
631 Server host performance During the login storm and steady state of the test the vSphere host CPU memory network and storage
performance were measured on all the servers that hosted the virtual desktops The performance of one
such vSphere server is given here The other vSphere servers had similar performance characteristics
Statistics for the vSphere hosts were captured by using VMware vCenter Server The figures here show the
CPU memory and network utilization for boot storm login storm and steady state of one of the vSphere
servers hosting the virtual desktops The results shown here are for a test run with 800 no standard user
desktops in the desktop pool
27 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 9 Average CPU performance per core on one vSphere host during login storm and steady state
Figure 10 Disk space usage during login storm and steady state
0
10
20
30
40
50
60
70
80
90
100
1020 1045 1110 1135 1200 1225
Per
cen
t
Time
CPU Performance
0
50
100
150
200
250
300
1020 1040 1100 1120 1140 1200 1220
GB
Time
Memory Performance
Granted Swap used Shared common
28 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 11 Overall network performance during login storm and steady state
Figure 12 Storage adapter performance during login storm and steady state
0
10000
20000
30000
40000
50000
60000
70000
1020 1045 1110 1135 1200 1225
kBp
s
Time
Network Performance
0
05
1
15
2
25
1020 1045 1110 1135 1200 1225
mSe
c
Time
Storage adaptor performance
29 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
The key observations from the statistics were
CPU utilization was less than the 85 percent threshold throughout the test
Active disk space usage was about 80 percent during the boost storm and about 60 percent
during login storm and steady state There was minimal-or no memory ballooning observed
Network utilization was about 45 percent which included all the networks such as iSCSI SAN VDI
LAN Management LAN and vMotion LAN
Average read- and write latencies at the storage adapter level were very close to the observed
latencies in Fluid Cache 2 msec
632 Monitoring user experience Figure 13 here shows the response time as experienced by each user as calculated by Login VSI The graph
clearly shows that the VSImax (Dynamic) value has not been reached and there were non-responsive or
inactive sessions This means that the array is capable of supporting the 1000 desktops and all users have
acceptable response times for applications that the user is has started
Figure 13 Login VSI user experience monitoring for 800 standard user desktops
30 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
633 Standard user test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SANndashbased VDI solution is able to host 800 virtual desktops and support
a standard user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only operations and
less than 2 percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to handle this login storm easily with low latency mdash it delivered the required 6500 IOPS with less
than 2 milliseconds of write latency with a 99 percent write VDI IO workload
64 Login storm and steady state with high IOPS (LoginVSI Medium +
Iometer) As mentioned earlier Iometer was used in desktop VMs alongside the Login VSI Medium workload to
simulate high IOPS type of VDI environment To mimic actual VDI workload profile the following Iometer
profile was used
20 KB block size 80 percent write 75 percent random with 25 msec burst delay
Figure 14 here shows the various IO characteristics during the login storm and steady state of these tests
Figure 14 IOPS and Cache Hit for the high IOPS test
On the Fluid Cache layer the maximum IOPS reached was approximately 72000 (or 90 IOPSVM) with
cache write-hit 100 percent and read-hit around 95 percent As shown in the Figure 15 the throughput
peaked at greater than 900 MBps with a peak latency of approximately 75 msec
31 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 15 Throughput and Latency for the high IOPS test
32 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
641 Server host performance Similar to the standard user test statistics for the vSphere hosts were captured by using VMware vCenter
Server during the high IOPS (heavy user) test also There are no significant differences in CPU disk space
and network utilization between standard users and heavy users The storage adapter latency is also
showing similar on hosts and observed on Fluid Cache
642 User experience monitoring Figure 16 here shows the response time as experienced by each user as calculated by Login VSI for the
heavy user test The graph shows that the VSImax (Dynamic) value was 796 indicating that the solution is
capable of supporting the 800 user high IOPS desktops with 90 IOPSVM
Figure 16 Login VSI user experience monitoring for 800 user high IOPS desktops
33 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
643 High IOPS (heavy user) test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SAN based VDI solution is able to host 800 virtual desktops and support a
high user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only and less than 2
percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to easily handle this login storm with low latency Subsequently it was able to handle 72000 IOPS
at high IOPS steady state with 90 IOPSVM with a maximum of 75 msec latency
34 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
7 Best practices This section provides the best practices derived from the testing and analysis in Section 6
71 Virtual Desktop Infrastructure This section provides best practices for the implementation of VDI using Dell Fluid Cache for SAN
711 Implement roaming profiles and folder redirection Dell recommends that all users in the VDI environment be configured with roaming profiles and folder
redirection This preserves user profiles and user data across boots while using non-persistent virtual
desktops
Also Dell recommends to use a high performance file service to provide the profile and folder redirection
A separate array may be used to host these volumes for best performance
712 Boot and login storm considerations Section 62 demonstrated the Fluid Cache for SAN performance under boot storm To avoid any potential
IO bursts because of boot storm and degraded user experience and performances Dell recommends that
all or portion of desktops be prebooted Connection brokers such as VMware Horizon View provide the
functionality to configure number of standby desktops
713 Windows 7 master image for desktop VMs Dell recommends that the operating system be customized in order to provide the best performance in a
VDI environment This includes disabling some services which may not be required This can improve
performance for the end user VMware has a specific set of recommendations and settings for Windows 7
and Windows 8 that allow for faster logins quicker screen refreshes and generally better performance
The VMware recommendations for Windows 7 and Windows 8 image optimization can be found here
httpwwwvmwarecomresourcestechresources10157
714 VDI Management infrastructure recommendations Dell recommends to have redundancy and load balancing for all VDI management services in the case of
VMware Horizon View solution as tested here the vSphere Server VMware Horizon View Servers and SQL
Servers Ideally these should be running on clustered hosts with VMware vSphere DRS (distributed
resource scheduler) and HA (high availability) enabled
72 Server host The vSphere servers hosting the infrastructure service providers and the virtual desktops are
recommended to be configured as follows
35 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Follow VMware and Dell best practices for installing and configuring vSphere
Separate virtual switches to segregate iSCSI SAN traffic VDI traffic vMotion traffic and Management
network traffic
Each network path must be assigned to a minimum of two physical NICs for high availability
VMware Knowledge Base article about best practices for installing vSphere 55
httpkbvmwarecomkb2052329
73 Network layer Dell recommends that at least two physical NICs on each vSphere server be dedicated to the VDI network
Use VLANs to segregate different types of network traffic on the same physical network In this case Dell
recommends to separate the infrastructure vMotion and VDI LAN traffic in to separate VLANs
Do not use VLANs to segregate iSCSI SAN and Fluide Cache traffic It is required that SAN and Cache traffic
be on separate dedicated physical network to provide the best performance
Virtual switches in vSphere have a default limit of 120 ports If the number of virtual desktops on each host
exceeds the available ports vSwitch properties should be changed to support the required number of
virtual desktops This change requires a restart of the host vSphere server
On iSCSI SAN switches Spanning tree must be disabled on switch ports connected to end devices for
server and storage ports The PortFast setting must be enabled in the switch configuration for these ports
Jumbo frames and Flow control (if the NICs support it) should be enabled for all components of the iSCSI
network
More information about configuring Dell Networking switches for use with Dell Storage iSCSI SANs is
available here
httpencommunitydellcomtechcenterstoragewwiki4250switch-configuration-guides-by-sisaspx
74 Storage The Dell SC storage arrays combined with Fluid Cache is an excellent platform for providing cost-effective
performance in VDI environments
Fluid Cache for SAN extends the power of Compellent intelligent data placement from the SAN to the
server By providing a single infrastructure for data at both high- and low ends of the performance
spectrum Fluid Cache for SAN with Storage Center 65 array software eliminates the tradeoffs between
server performance and full-featured SAN benefits such as reliability manageability and data protection
Dell recommends to have separate volumes for base image and virtual desktops This enables better
manageability of the volumes easier performance monitoring and allows easy future growth
Dell recommends to use a separate high performance file service to provide file shares for roaming
profiles and user shares
36 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
8 Conclusion The technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed by using a Horizon View VDI platform leveraging Dell Fluid Cache for SAN The storage IO
characteristics under various VDI workload scenarios (boot storm login storm and steady state) along
with performance characteristics throughout the VDI stack (for example vSphere server performance and
user experience) demonstrate the optimal configuration of the infrastructure used for this VDI
deployment For more information about Fluid Cache contact your Dell account manager
37 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
A Horizon view solution configuration
Table 7 Hardware components
Hardware components Description
Virtual Desktops 4 timesDell PowerEdge R720 Servers (Fluid Cache Providers)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
2times350 GB Dell Express Flash PCIe SSDs
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
4 x Dell PowerEdge R720 Servers (Fluid Cache Clients)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55 U2 on all R720 servers Windows 7 (64 Bit) VMs
Infrastructure Servers 2 x Dell PowerEdge R720 servers
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
96 GB RAM
2times300 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55U2 on all R720 servers VMs are loaded with Microsoft Windows 2008 R2
Active Directory
VMware Horizon View 60 Server 1
VMware Horizon View 60 Server 2
VMware vCenter Server 55 update 2
VMware Horizon View Composer
SQL Server
File Server
Login VSI Launchers 8 x Dell PowerEdge M610 servers
2timesIntelreg Xeonreg E-5503 200 GHz Processors
16 GB RAM
4times146 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57711 10GbE NIC
ESXi 51 installed on all R810 servers VMs are loaded with Microsoft Windows 7 64bit Each VM supports up to 30 Login VSI launcher sessions
38 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Network Management VDI LAN
1timesDell Force10 S55 1Gb Ethernet Switch
iSCSI SAN
1timesDell Force10 S4810 10Gb Ethernet Switch
Cache network
1timesDell Force10 S4810 10Gb Ethernet Switch
One Force10 S4810 switch might suffice for all the cache iSCSI SAN VDI LAN and management traffic
Storage 2timesDell Compellent SC8000 controllers 4times6Gb SAS 4-port PCI-E Full-height cards for back-end connectivity 2times10Gb iSCSI 2 port PCI-E Low-profile IO cards for front end connectivity 1timesDell Compellent SC200 disk enclosures 12times4TB NL-SAS 6Gb 72K 35rdquo drives
User Data Infrastructure VMs Virtual Desktops
Performance Monitoring
Dell Compellent Enterprise Manager Dell Fluid Cache for SAN performance monitoring tool () vCenter Performance monitoring Liquidware Stratusphere UX
Performance monitoring on Compellent arrays Fluid Cache performance monitoring Performance monitoring and capture at the ESXi host User experience monitoring on the virtual desktop
39 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 8 Software components
Software components Description Version
Dell Fluid Cache for SAN 20
Dell Compellent Storage Center 64
Dell Compellent Enterprise Manager 64
VMware Horizon View Server 60
VMware Horizon View Composer 60
VMware Horizon View Agent 60
VMware Horizon View Client 64-bit 60
VMware ESXi Hypervisor 55 U2
VMware vCenter Server 55 U2
Microsoft SQL Server 2008R2 Enterprise x64 105016001
Client VM OS Microsoft Windows 7 Enterprise x64 SP1
Management VM OS Microsoft Windows Server 2008 Enterprise R2 x64 SP1
Microsoft Office MS office 2010 Standard Service Pack 1
Login VSI Version 40
Iometer 20060727
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
19 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
5 Horizon view test methodology This section outlines the test objectives along with the test tools and criteria used to determine the
optimal virtual desktop density and best practices for deploying Horizon View on Dell Fluid Cache for SAN
for high IOPS type VDI environment
51 Test objectives As noted in Section 11 the test objectives were
Develop an optimal end-to-end infrastructure design for a Horizon View and vSpherendashbased high
user type of VDI solution deployed by using the Fluid Cache Compellent storage PowerEdge
servers and Dell Networking switches
Determine the performance at every layer of the VDI solution stack under high IOPS workload For
example desktops generating 80ndash90 IOPSVM at steady state
Determine the performance impact of peak IO activity such as boot and login storms
52 Test tools All tests were conducted by using Login VSI 40 as the workload generator and user experience analyzer
tool Login VSI is a benchmarking tool to measure the performance and scalability of centralized desktop
environments such as Server Based Computing (SBC) and VDI
Note More information can be found at the Login VSI website httpwwwloginvsicom
In addition to Login VSI Iometer is used in desktop VMs to simulate high IOPS conditions Iometer is
invoked in desktop VMs by using custom scripting of Login VSI workloads
Note More information can be found at the Iometer project website httpwwwiometerorg
521 Load generation First the ldquoMediumrdquo workload from Login VSI was used to simulate the standard user workload The
characteristics of the Medium workload are
Up to five applications are started simultaneously
Applications include Microsoft Internet Explorer Microsoft Word Microsoft Excel Microsoft
PowerPoint PDF reader 7-Zip compression software Movie player and FreeMind
After a session is started the medium workload repeats approximately after every 48 minutes
During a loop the response time is measured after every 3ndash4 minutes
Idle time is about two minutes in each 48-minute loop
Type rate is approximately 160 milliseconds per character
After the test by using Login VSI Medium was complete tests were rerun with Login VSI Medium and
Iometer in desktop VMs to simulate high IOPS VDI workload While the Login VSI Medium generates 8ndash10
20 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
IOPSVM the latter method was able to generate 80ndash90 IOPSVM For these tests each VM in the Horizon
view pool is created with standard LoginVSI contents and applications Also Iometer is installed on each
VM After the user logs in a customized logon script starts the Iometer with required IO specification (icf
file)
522 Monitoring tools The following monitoring tools were used
Dell Compellent Enterprise Manager for monitoring Fluid Cache and Compellent SC8000 storage
array performance
VMware vCenter statistics for vSphere performance
Login VSI Analyzer for end user performance statistics
Detailed performance metrics were captured from the storage arrays hypervisors virtual desktops and
the load generators during the tests
53 Test criteria The primary focus of the tests is to validate the 800 desktop high IOPS type of VDI architecture with
acceptable user experience by using Fluid Cache for SAN VDI configurations involve many components at
different layers ndash application hypervisor server network and storage As a result multiple metrics need to
be captured at different layers to ensure that the environment is healthy and performing optimally and
appropriately for all users
The specific test criteria are described in the following sections
531 Storage capacity and IO latency The typical industry standard latency limit for storage disk IO is 10 milliseconds Maintaining this limit
ensures good user application response times when there are no other bottlenecks at the infrastructure
layer In addition Dell recommends to maintain a 10 percent spare disk space on the storage array for
optimal performance
532 System utilization at the hypervisor Even though the primary focus of these tests was storage characterization additional metrics at the
hypervisor infrastructure layer were defined to ensure solution consistency These were
CPU utilization on any vSphere server must not exceed 85 percent
Minimal memory ballooning on the VMs
Total network bandwidth utilization must not exceed 90 percent on any one link
TCPIP storage network retransmissions should be less than 05 percent
21 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
533 Virtual desktop user experience Login VSI Analyzer was also used to gather metrics on the user experience at the virtual desktop layer to
ensure that all the desktops had acceptable levels of application performance Login VSI uses the VSImax
parameter to determine the maximum number of sessions that can be obtained from a deployed solution
The calculation methodology used in VSImax is available here
httpwwwloginvsicomdocumentationindexphptitle=Analyzing_Results
534 Test configuration A single virtual desktop pool was configured by using the VMware Horizon View Administrator interface
Each pool was built from a Windows 7 base image The Windows 7 configuration information is available
in Section 46
Desktop pool properties
Automatic Desktop Pool
Users are assigned using Floating assignments
View Storage Accelerator is enabled for all hosts with a refresh period of seven days
800 desktops were deployed across eight hosts (100 desktops a host)
Replica images were stored on a separate volume
22 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
6 Test results and analysis This section presents the results from the different Horizon View VDI characterization tests and the key
findings from each test The testing was focused on the high IOPS workload profile
61 Test scenarios The following tests were conducted to gather results and analysis on the solution stack
1 Boot storm Boot storms represent the worst-case scenario where many virtual desktops are
turned on at the same time and they all contend for the system resources simultaneously This test
was used to evaluate if the storage array hosting the desktops was capable of handling huge
variation in storage IO without causing significant impact on other services
2 Login storm Login storms also represent a high IOPS situation where many users are logging in to
their virtual desktops at the beginning of a workday or a shift In this test all the desktops were
pre-booted and left in an idle state for more than 20 minutes to let their IO settle before running
the Login VSI Medium workload to simulate users logging in to their virtual desktops
3 Steady state workload for standard users with normal IOPS After the login storm for the previous
test was completed the Login VSI Medium workload was allowed to run for at least one hour to
simulate the real-world scenario of users performing their daily tasks The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
4 Steady state workload for users with high IOPS The previous test was repeated with the Login
VSI Medium workload and Iometer scripts in desktop VMs as described in Section 521 to simulate
real-world heavy users performing their daily tasks with high IOPS The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
The following sections provide results from the boot storm login storm and steady state testing for the
Fluid Cache for SAN based VDI solution
23 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
62 Boot storm IO To simulate a boot storm the virtual desktops were reset simultaneously from the VMware vSphere client
Figure 6 shows the IO pattern on the Fluid Cache for the boot storm
Figure 6 SAN HQ data showing boot storm performance with Fluid Cache array
With 800 desktops the boot storm generated about 115000 total IOPS with a majority of them being
write operations All desktops were available for use in less than four minutes
24 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
63 Login storm and steady state for standard users (LoginVSI
Medium) Login VSI was programmed to start 800 virtual desktops over a period of about 60 minutes after pre-
booting the virtual desktops The peak IOPS during the login storm observed by the vSphere servers
hosting the desktops was about 6500 IOPS (8ndash10 IOPS a VM)
In a standard user environment login storms generate significantly more write IOPS than a boot storm or
steady state because of multiple factors such as
User profile activity
Starting operating system services on the desktop
First start of applications
After a virtual desktop has achieved a steady state after user login the Windows 7 OS has cached
applications in memory and does not need to access storage each time the application is started This
leads to lesser IOPS during the steady state Figure 7 here shows the various IO characteristics during the
login storm and steady state of these tests
25 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 7 IOPS and Cache Hit for the standard user test
On the Fluid Cache layer the maximum IOPS reached 6500 with cache-hit reaching 100 percent and
read-hit around 95 percent As shown in the Figure 8 here the throughput peaked at 98 MBps with a low
latency of less than 2 msec
26 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 8 Throughput and Latency for the standard user test
631 Server host performance During the login storm and steady state of the test the vSphere host CPU memory network and storage
performance were measured on all the servers that hosted the virtual desktops The performance of one
such vSphere server is given here The other vSphere servers had similar performance characteristics
Statistics for the vSphere hosts were captured by using VMware vCenter Server The figures here show the
CPU memory and network utilization for boot storm login storm and steady state of one of the vSphere
servers hosting the virtual desktops The results shown here are for a test run with 800 no standard user
desktops in the desktop pool
27 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 9 Average CPU performance per core on one vSphere host during login storm and steady state
Figure 10 Disk space usage during login storm and steady state
0
10
20
30
40
50
60
70
80
90
100
1020 1045 1110 1135 1200 1225
Per
cen
t
Time
CPU Performance
0
50
100
150
200
250
300
1020 1040 1100 1120 1140 1200 1220
GB
Time
Memory Performance
Granted Swap used Shared common
28 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 11 Overall network performance during login storm and steady state
Figure 12 Storage adapter performance during login storm and steady state
0
10000
20000
30000
40000
50000
60000
70000
1020 1045 1110 1135 1200 1225
kBp
s
Time
Network Performance
0
05
1
15
2
25
1020 1045 1110 1135 1200 1225
mSe
c
Time
Storage adaptor performance
29 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
The key observations from the statistics were
CPU utilization was less than the 85 percent threshold throughout the test
Active disk space usage was about 80 percent during the boost storm and about 60 percent
during login storm and steady state There was minimal-or no memory ballooning observed
Network utilization was about 45 percent which included all the networks such as iSCSI SAN VDI
LAN Management LAN and vMotion LAN
Average read- and write latencies at the storage adapter level were very close to the observed
latencies in Fluid Cache 2 msec
632 Monitoring user experience Figure 13 here shows the response time as experienced by each user as calculated by Login VSI The graph
clearly shows that the VSImax (Dynamic) value has not been reached and there were non-responsive or
inactive sessions This means that the array is capable of supporting the 1000 desktops and all users have
acceptable response times for applications that the user is has started
Figure 13 Login VSI user experience monitoring for 800 standard user desktops
30 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
633 Standard user test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SANndashbased VDI solution is able to host 800 virtual desktops and support
a standard user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only operations and
less than 2 percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to handle this login storm easily with low latency mdash it delivered the required 6500 IOPS with less
than 2 milliseconds of write latency with a 99 percent write VDI IO workload
64 Login storm and steady state with high IOPS (LoginVSI Medium +
Iometer) As mentioned earlier Iometer was used in desktop VMs alongside the Login VSI Medium workload to
simulate high IOPS type of VDI environment To mimic actual VDI workload profile the following Iometer
profile was used
20 KB block size 80 percent write 75 percent random with 25 msec burst delay
Figure 14 here shows the various IO characteristics during the login storm and steady state of these tests
Figure 14 IOPS and Cache Hit for the high IOPS test
On the Fluid Cache layer the maximum IOPS reached was approximately 72000 (or 90 IOPSVM) with
cache write-hit 100 percent and read-hit around 95 percent As shown in the Figure 15 the throughput
peaked at greater than 900 MBps with a peak latency of approximately 75 msec
31 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 15 Throughput and Latency for the high IOPS test
32 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
641 Server host performance Similar to the standard user test statistics for the vSphere hosts were captured by using VMware vCenter
Server during the high IOPS (heavy user) test also There are no significant differences in CPU disk space
and network utilization between standard users and heavy users The storage adapter latency is also
showing similar on hosts and observed on Fluid Cache
642 User experience monitoring Figure 16 here shows the response time as experienced by each user as calculated by Login VSI for the
heavy user test The graph shows that the VSImax (Dynamic) value was 796 indicating that the solution is
capable of supporting the 800 user high IOPS desktops with 90 IOPSVM
Figure 16 Login VSI user experience monitoring for 800 user high IOPS desktops
33 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
643 High IOPS (heavy user) test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SAN based VDI solution is able to host 800 virtual desktops and support a
high user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only and less than 2
percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to easily handle this login storm with low latency Subsequently it was able to handle 72000 IOPS
at high IOPS steady state with 90 IOPSVM with a maximum of 75 msec latency
34 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
7 Best practices This section provides the best practices derived from the testing and analysis in Section 6
71 Virtual Desktop Infrastructure This section provides best practices for the implementation of VDI using Dell Fluid Cache for SAN
711 Implement roaming profiles and folder redirection Dell recommends that all users in the VDI environment be configured with roaming profiles and folder
redirection This preserves user profiles and user data across boots while using non-persistent virtual
desktops
Also Dell recommends to use a high performance file service to provide the profile and folder redirection
A separate array may be used to host these volumes for best performance
712 Boot and login storm considerations Section 62 demonstrated the Fluid Cache for SAN performance under boot storm To avoid any potential
IO bursts because of boot storm and degraded user experience and performances Dell recommends that
all or portion of desktops be prebooted Connection brokers such as VMware Horizon View provide the
functionality to configure number of standby desktops
713 Windows 7 master image for desktop VMs Dell recommends that the operating system be customized in order to provide the best performance in a
VDI environment This includes disabling some services which may not be required This can improve
performance for the end user VMware has a specific set of recommendations and settings for Windows 7
and Windows 8 that allow for faster logins quicker screen refreshes and generally better performance
The VMware recommendations for Windows 7 and Windows 8 image optimization can be found here
httpwwwvmwarecomresourcestechresources10157
714 VDI Management infrastructure recommendations Dell recommends to have redundancy and load balancing for all VDI management services in the case of
VMware Horizon View solution as tested here the vSphere Server VMware Horizon View Servers and SQL
Servers Ideally these should be running on clustered hosts with VMware vSphere DRS (distributed
resource scheduler) and HA (high availability) enabled
72 Server host The vSphere servers hosting the infrastructure service providers and the virtual desktops are
recommended to be configured as follows
35 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Follow VMware and Dell best practices for installing and configuring vSphere
Separate virtual switches to segregate iSCSI SAN traffic VDI traffic vMotion traffic and Management
network traffic
Each network path must be assigned to a minimum of two physical NICs for high availability
VMware Knowledge Base article about best practices for installing vSphere 55
httpkbvmwarecomkb2052329
73 Network layer Dell recommends that at least two physical NICs on each vSphere server be dedicated to the VDI network
Use VLANs to segregate different types of network traffic on the same physical network In this case Dell
recommends to separate the infrastructure vMotion and VDI LAN traffic in to separate VLANs
Do not use VLANs to segregate iSCSI SAN and Fluide Cache traffic It is required that SAN and Cache traffic
be on separate dedicated physical network to provide the best performance
Virtual switches in vSphere have a default limit of 120 ports If the number of virtual desktops on each host
exceeds the available ports vSwitch properties should be changed to support the required number of
virtual desktops This change requires a restart of the host vSphere server
On iSCSI SAN switches Spanning tree must be disabled on switch ports connected to end devices for
server and storage ports The PortFast setting must be enabled in the switch configuration for these ports
Jumbo frames and Flow control (if the NICs support it) should be enabled for all components of the iSCSI
network
More information about configuring Dell Networking switches for use with Dell Storage iSCSI SANs is
available here
httpencommunitydellcomtechcenterstoragewwiki4250switch-configuration-guides-by-sisaspx
74 Storage The Dell SC storage arrays combined with Fluid Cache is an excellent platform for providing cost-effective
performance in VDI environments
Fluid Cache for SAN extends the power of Compellent intelligent data placement from the SAN to the
server By providing a single infrastructure for data at both high- and low ends of the performance
spectrum Fluid Cache for SAN with Storage Center 65 array software eliminates the tradeoffs between
server performance and full-featured SAN benefits such as reliability manageability and data protection
Dell recommends to have separate volumes for base image and virtual desktops This enables better
manageability of the volumes easier performance monitoring and allows easy future growth
Dell recommends to use a separate high performance file service to provide file shares for roaming
profiles and user shares
36 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
8 Conclusion The technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed by using a Horizon View VDI platform leveraging Dell Fluid Cache for SAN The storage IO
characteristics under various VDI workload scenarios (boot storm login storm and steady state) along
with performance characteristics throughout the VDI stack (for example vSphere server performance and
user experience) demonstrate the optimal configuration of the infrastructure used for this VDI
deployment For more information about Fluid Cache contact your Dell account manager
37 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
A Horizon view solution configuration
Table 7 Hardware components
Hardware components Description
Virtual Desktops 4 timesDell PowerEdge R720 Servers (Fluid Cache Providers)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
2times350 GB Dell Express Flash PCIe SSDs
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
4 x Dell PowerEdge R720 Servers (Fluid Cache Clients)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55 U2 on all R720 servers Windows 7 (64 Bit) VMs
Infrastructure Servers 2 x Dell PowerEdge R720 servers
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
96 GB RAM
2times300 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55U2 on all R720 servers VMs are loaded with Microsoft Windows 2008 R2
Active Directory
VMware Horizon View 60 Server 1
VMware Horizon View 60 Server 2
VMware vCenter Server 55 update 2
VMware Horizon View Composer
SQL Server
File Server
Login VSI Launchers 8 x Dell PowerEdge M610 servers
2timesIntelreg Xeonreg E-5503 200 GHz Processors
16 GB RAM
4times146 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57711 10GbE NIC
ESXi 51 installed on all R810 servers VMs are loaded with Microsoft Windows 7 64bit Each VM supports up to 30 Login VSI launcher sessions
38 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Network Management VDI LAN
1timesDell Force10 S55 1Gb Ethernet Switch
iSCSI SAN
1timesDell Force10 S4810 10Gb Ethernet Switch
Cache network
1timesDell Force10 S4810 10Gb Ethernet Switch
One Force10 S4810 switch might suffice for all the cache iSCSI SAN VDI LAN and management traffic
Storage 2timesDell Compellent SC8000 controllers 4times6Gb SAS 4-port PCI-E Full-height cards for back-end connectivity 2times10Gb iSCSI 2 port PCI-E Low-profile IO cards for front end connectivity 1timesDell Compellent SC200 disk enclosures 12times4TB NL-SAS 6Gb 72K 35rdquo drives
User Data Infrastructure VMs Virtual Desktops
Performance Monitoring
Dell Compellent Enterprise Manager Dell Fluid Cache for SAN performance monitoring tool () vCenter Performance monitoring Liquidware Stratusphere UX
Performance monitoring on Compellent arrays Fluid Cache performance monitoring Performance monitoring and capture at the ESXi host User experience monitoring on the virtual desktop
39 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 8 Software components
Software components Description Version
Dell Fluid Cache for SAN 20
Dell Compellent Storage Center 64
Dell Compellent Enterprise Manager 64
VMware Horizon View Server 60
VMware Horizon View Composer 60
VMware Horizon View Agent 60
VMware Horizon View Client 64-bit 60
VMware ESXi Hypervisor 55 U2
VMware vCenter Server 55 U2
Microsoft SQL Server 2008R2 Enterprise x64 105016001
Client VM OS Microsoft Windows 7 Enterprise x64 SP1
Management VM OS Microsoft Windows Server 2008 Enterprise R2 x64 SP1
Microsoft Office MS office 2010 Standard Service Pack 1
Login VSI Version 40
Iometer 20060727
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
20 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
IOPSVM the latter method was able to generate 80ndash90 IOPSVM For these tests each VM in the Horizon
view pool is created with standard LoginVSI contents and applications Also Iometer is installed on each
VM After the user logs in a customized logon script starts the Iometer with required IO specification (icf
file)
522 Monitoring tools The following monitoring tools were used
Dell Compellent Enterprise Manager for monitoring Fluid Cache and Compellent SC8000 storage
array performance
VMware vCenter statistics for vSphere performance
Login VSI Analyzer for end user performance statistics
Detailed performance metrics were captured from the storage arrays hypervisors virtual desktops and
the load generators during the tests
53 Test criteria The primary focus of the tests is to validate the 800 desktop high IOPS type of VDI architecture with
acceptable user experience by using Fluid Cache for SAN VDI configurations involve many components at
different layers ndash application hypervisor server network and storage As a result multiple metrics need to
be captured at different layers to ensure that the environment is healthy and performing optimally and
appropriately for all users
The specific test criteria are described in the following sections
531 Storage capacity and IO latency The typical industry standard latency limit for storage disk IO is 10 milliseconds Maintaining this limit
ensures good user application response times when there are no other bottlenecks at the infrastructure
layer In addition Dell recommends to maintain a 10 percent spare disk space on the storage array for
optimal performance
532 System utilization at the hypervisor Even though the primary focus of these tests was storage characterization additional metrics at the
hypervisor infrastructure layer were defined to ensure solution consistency These were
CPU utilization on any vSphere server must not exceed 85 percent
Minimal memory ballooning on the VMs
Total network bandwidth utilization must not exceed 90 percent on any one link
TCPIP storage network retransmissions should be less than 05 percent
21 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
533 Virtual desktop user experience Login VSI Analyzer was also used to gather metrics on the user experience at the virtual desktop layer to
ensure that all the desktops had acceptable levels of application performance Login VSI uses the VSImax
parameter to determine the maximum number of sessions that can be obtained from a deployed solution
The calculation methodology used in VSImax is available here
httpwwwloginvsicomdocumentationindexphptitle=Analyzing_Results
534 Test configuration A single virtual desktop pool was configured by using the VMware Horizon View Administrator interface
Each pool was built from a Windows 7 base image The Windows 7 configuration information is available
in Section 46
Desktop pool properties
Automatic Desktop Pool
Users are assigned using Floating assignments
View Storage Accelerator is enabled for all hosts with a refresh period of seven days
800 desktops were deployed across eight hosts (100 desktops a host)
Replica images were stored on a separate volume
22 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
6 Test results and analysis This section presents the results from the different Horizon View VDI characterization tests and the key
findings from each test The testing was focused on the high IOPS workload profile
61 Test scenarios The following tests were conducted to gather results and analysis on the solution stack
1 Boot storm Boot storms represent the worst-case scenario where many virtual desktops are
turned on at the same time and they all contend for the system resources simultaneously This test
was used to evaluate if the storage array hosting the desktops was capable of handling huge
variation in storage IO without causing significant impact on other services
2 Login storm Login storms also represent a high IOPS situation where many users are logging in to
their virtual desktops at the beginning of a workday or a shift In this test all the desktops were
pre-booted and left in an idle state for more than 20 minutes to let their IO settle before running
the Login VSI Medium workload to simulate users logging in to their virtual desktops
3 Steady state workload for standard users with normal IOPS After the login storm for the previous
test was completed the Login VSI Medium workload was allowed to run for at least one hour to
simulate the real-world scenario of users performing their daily tasks The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
4 Steady state workload for users with high IOPS The previous test was repeated with the Login
VSI Medium workload and Iometer scripts in desktop VMs as described in Section 521 to simulate
real-world heavy users performing their daily tasks with high IOPS The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
The following sections provide results from the boot storm login storm and steady state testing for the
Fluid Cache for SAN based VDI solution
23 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
62 Boot storm IO To simulate a boot storm the virtual desktops were reset simultaneously from the VMware vSphere client
Figure 6 shows the IO pattern on the Fluid Cache for the boot storm
Figure 6 SAN HQ data showing boot storm performance with Fluid Cache array
With 800 desktops the boot storm generated about 115000 total IOPS with a majority of them being
write operations All desktops were available for use in less than four minutes
24 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
63 Login storm and steady state for standard users (LoginVSI
Medium) Login VSI was programmed to start 800 virtual desktops over a period of about 60 minutes after pre-
booting the virtual desktops The peak IOPS during the login storm observed by the vSphere servers
hosting the desktops was about 6500 IOPS (8ndash10 IOPS a VM)
In a standard user environment login storms generate significantly more write IOPS than a boot storm or
steady state because of multiple factors such as
User profile activity
Starting operating system services on the desktop
First start of applications
After a virtual desktop has achieved a steady state after user login the Windows 7 OS has cached
applications in memory and does not need to access storage each time the application is started This
leads to lesser IOPS during the steady state Figure 7 here shows the various IO characteristics during the
login storm and steady state of these tests
25 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 7 IOPS and Cache Hit for the standard user test
On the Fluid Cache layer the maximum IOPS reached 6500 with cache-hit reaching 100 percent and
read-hit around 95 percent As shown in the Figure 8 here the throughput peaked at 98 MBps with a low
latency of less than 2 msec
26 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 8 Throughput and Latency for the standard user test
631 Server host performance During the login storm and steady state of the test the vSphere host CPU memory network and storage
performance were measured on all the servers that hosted the virtual desktops The performance of one
such vSphere server is given here The other vSphere servers had similar performance characteristics
Statistics for the vSphere hosts were captured by using VMware vCenter Server The figures here show the
CPU memory and network utilization for boot storm login storm and steady state of one of the vSphere
servers hosting the virtual desktops The results shown here are for a test run with 800 no standard user
desktops in the desktop pool
27 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 9 Average CPU performance per core on one vSphere host during login storm and steady state
Figure 10 Disk space usage during login storm and steady state
0
10
20
30
40
50
60
70
80
90
100
1020 1045 1110 1135 1200 1225
Per
cen
t
Time
CPU Performance
0
50
100
150
200
250
300
1020 1040 1100 1120 1140 1200 1220
GB
Time
Memory Performance
Granted Swap used Shared common
28 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 11 Overall network performance during login storm and steady state
Figure 12 Storage adapter performance during login storm and steady state
0
10000
20000
30000
40000
50000
60000
70000
1020 1045 1110 1135 1200 1225
kBp
s
Time
Network Performance
0
05
1
15
2
25
1020 1045 1110 1135 1200 1225
mSe
c
Time
Storage adaptor performance
29 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
The key observations from the statistics were
CPU utilization was less than the 85 percent threshold throughout the test
Active disk space usage was about 80 percent during the boost storm and about 60 percent
during login storm and steady state There was minimal-or no memory ballooning observed
Network utilization was about 45 percent which included all the networks such as iSCSI SAN VDI
LAN Management LAN and vMotion LAN
Average read- and write latencies at the storage adapter level were very close to the observed
latencies in Fluid Cache 2 msec
632 Monitoring user experience Figure 13 here shows the response time as experienced by each user as calculated by Login VSI The graph
clearly shows that the VSImax (Dynamic) value has not been reached and there were non-responsive or
inactive sessions This means that the array is capable of supporting the 1000 desktops and all users have
acceptable response times for applications that the user is has started
Figure 13 Login VSI user experience monitoring for 800 standard user desktops
30 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
633 Standard user test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SANndashbased VDI solution is able to host 800 virtual desktops and support
a standard user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only operations and
less than 2 percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to handle this login storm easily with low latency mdash it delivered the required 6500 IOPS with less
than 2 milliseconds of write latency with a 99 percent write VDI IO workload
64 Login storm and steady state with high IOPS (LoginVSI Medium +
Iometer) As mentioned earlier Iometer was used in desktop VMs alongside the Login VSI Medium workload to
simulate high IOPS type of VDI environment To mimic actual VDI workload profile the following Iometer
profile was used
20 KB block size 80 percent write 75 percent random with 25 msec burst delay
Figure 14 here shows the various IO characteristics during the login storm and steady state of these tests
Figure 14 IOPS and Cache Hit for the high IOPS test
On the Fluid Cache layer the maximum IOPS reached was approximately 72000 (or 90 IOPSVM) with
cache write-hit 100 percent and read-hit around 95 percent As shown in the Figure 15 the throughput
peaked at greater than 900 MBps with a peak latency of approximately 75 msec
31 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 15 Throughput and Latency for the high IOPS test
32 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
641 Server host performance Similar to the standard user test statistics for the vSphere hosts were captured by using VMware vCenter
Server during the high IOPS (heavy user) test also There are no significant differences in CPU disk space
and network utilization between standard users and heavy users The storage adapter latency is also
showing similar on hosts and observed on Fluid Cache
642 User experience monitoring Figure 16 here shows the response time as experienced by each user as calculated by Login VSI for the
heavy user test The graph shows that the VSImax (Dynamic) value was 796 indicating that the solution is
capable of supporting the 800 user high IOPS desktops with 90 IOPSVM
Figure 16 Login VSI user experience monitoring for 800 user high IOPS desktops
33 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
643 High IOPS (heavy user) test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SAN based VDI solution is able to host 800 virtual desktops and support a
high user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only and less than 2
percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to easily handle this login storm with low latency Subsequently it was able to handle 72000 IOPS
at high IOPS steady state with 90 IOPSVM with a maximum of 75 msec latency
34 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
7 Best practices This section provides the best practices derived from the testing and analysis in Section 6
71 Virtual Desktop Infrastructure This section provides best practices for the implementation of VDI using Dell Fluid Cache for SAN
711 Implement roaming profiles and folder redirection Dell recommends that all users in the VDI environment be configured with roaming profiles and folder
redirection This preserves user profiles and user data across boots while using non-persistent virtual
desktops
Also Dell recommends to use a high performance file service to provide the profile and folder redirection
A separate array may be used to host these volumes for best performance
712 Boot and login storm considerations Section 62 demonstrated the Fluid Cache for SAN performance under boot storm To avoid any potential
IO bursts because of boot storm and degraded user experience and performances Dell recommends that
all or portion of desktops be prebooted Connection brokers such as VMware Horizon View provide the
functionality to configure number of standby desktops
713 Windows 7 master image for desktop VMs Dell recommends that the operating system be customized in order to provide the best performance in a
VDI environment This includes disabling some services which may not be required This can improve
performance for the end user VMware has a specific set of recommendations and settings for Windows 7
and Windows 8 that allow for faster logins quicker screen refreshes and generally better performance
The VMware recommendations for Windows 7 and Windows 8 image optimization can be found here
httpwwwvmwarecomresourcestechresources10157
714 VDI Management infrastructure recommendations Dell recommends to have redundancy and load balancing for all VDI management services in the case of
VMware Horizon View solution as tested here the vSphere Server VMware Horizon View Servers and SQL
Servers Ideally these should be running on clustered hosts with VMware vSphere DRS (distributed
resource scheduler) and HA (high availability) enabled
72 Server host The vSphere servers hosting the infrastructure service providers and the virtual desktops are
recommended to be configured as follows
35 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Follow VMware and Dell best practices for installing and configuring vSphere
Separate virtual switches to segregate iSCSI SAN traffic VDI traffic vMotion traffic and Management
network traffic
Each network path must be assigned to a minimum of two physical NICs for high availability
VMware Knowledge Base article about best practices for installing vSphere 55
httpkbvmwarecomkb2052329
73 Network layer Dell recommends that at least two physical NICs on each vSphere server be dedicated to the VDI network
Use VLANs to segregate different types of network traffic on the same physical network In this case Dell
recommends to separate the infrastructure vMotion and VDI LAN traffic in to separate VLANs
Do not use VLANs to segregate iSCSI SAN and Fluide Cache traffic It is required that SAN and Cache traffic
be on separate dedicated physical network to provide the best performance
Virtual switches in vSphere have a default limit of 120 ports If the number of virtual desktops on each host
exceeds the available ports vSwitch properties should be changed to support the required number of
virtual desktops This change requires a restart of the host vSphere server
On iSCSI SAN switches Spanning tree must be disabled on switch ports connected to end devices for
server and storage ports The PortFast setting must be enabled in the switch configuration for these ports
Jumbo frames and Flow control (if the NICs support it) should be enabled for all components of the iSCSI
network
More information about configuring Dell Networking switches for use with Dell Storage iSCSI SANs is
available here
httpencommunitydellcomtechcenterstoragewwiki4250switch-configuration-guides-by-sisaspx
74 Storage The Dell SC storage arrays combined with Fluid Cache is an excellent platform for providing cost-effective
performance in VDI environments
Fluid Cache for SAN extends the power of Compellent intelligent data placement from the SAN to the
server By providing a single infrastructure for data at both high- and low ends of the performance
spectrum Fluid Cache for SAN with Storage Center 65 array software eliminates the tradeoffs between
server performance and full-featured SAN benefits such as reliability manageability and data protection
Dell recommends to have separate volumes for base image and virtual desktops This enables better
manageability of the volumes easier performance monitoring and allows easy future growth
Dell recommends to use a separate high performance file service to provide file shares for roaming
profiles and user shares
36 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
8 Conclusion The technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed by using a Horizon View VDI platform leveraging Dell Fluid Cache for SAN The storage IO
characteristics under various VDI workload scenarios (boot storm login storm and steady state) along
with performance characteristics throughout the VDI stack (for example vSphere server performance and
user experience) demonstrate the optimal configuration of the infrastructure used for this VDI
deployment For more information about Fluid Cache contact your Dell account manager
37 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
A Horizon view solution configuration
Table 7 Hardware components
Hardware components Description
Virtual Desktops 4 timesDell PowerEdge R720 Servers (Fluid Cache Providers)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
2times350 GB Dell Express Flash PCIe SSDs
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
4 x Dell PowerEdge R720 Servers (Fluid Cache Clients)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55 U2 on all R720 servers Windows 7 (64 Bit) VMs
Infrastructure Servers 2 x Dell PowerEdge R720 servers
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
96 GB RAM
2times300 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55U2 on all R720 servers VMs are loaded with Microsoft Windows 2008 R2
Active Directory
VMware Horizon View 60 Server 1
VMware Horizon View 60 Server 2
VMware vCenter Server 55 update 2
VMware Horizon View Composer
SQL Server
File Server
Login VSI Launchers 8 x Dell PowerEdge M610 servers
2timesIntelreg Xeonreg E-5503 200 GHz Processors
16 GB RAM
4times146 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57711 10GbE NIC
ESXi 51 installed on all R810 servers VMs are loaded with Microsoft Windows 7 64bit Each VM supports up to 30 Login VSI launcher sessions
38 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Network Management VDI LAN
1timesDell Force10 S55 1Gb Ethernet Switch
iSCSI SAN
1timesDell Force10 S4810 10Gb Ethernet Switch
Cache network
1timesDell Force10 S4810 10Gb Ethernet Switch
One Force10 S4810 switch might suffice for all the cache iSCSI SAN VDI LAN and management traffic
Storage 2timesDell Compellent SC8000 controllers 4times6Gb SAS 4-port PCI-E Full-height cards for back-end connectivity 2times10Gb iSCSI 2 port PCI-E Low-profile IO cards for front end connectivity 1timesDell Compellent SC200 disk enclosures 12times4TB NL-SAS 6Gb 72K 35rdquo drives
User Data Infrastructure VMs Virtual Desktops
Performance Monitoring
Dell Compellent Enterprise Manager Dell Fluid Cache for SAN performance monitoring tool () vCenter Performance monitoring Liquidware Stratusphere UX
Performance monitoring on Compellent arrays Fluid Cache performance monitoring Performance monitoring and capture at the ESXi host User experience monitoring on the virtual desktop
39 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 8 Software components
Software components Description Version
Dell Fluid Cache for SAN 20
Dell Compellent Storage Center 64
Dell Compellent Enterprise Manager 64
VMware Horizon View Server 60
VMware Horizon View Composer 60
VMware Horizon View Agent 60
VMware Horizon View Client 64-bit 60
VMware ESXi Hypervisor 55 U2
VMware vCenter Server 55 U2
Microsoft SQL Server 2008R2 Enterprise x64 105016001
Client VM OS Microsoft Windows 7 Enterprise x64 SP1
Management VM OS Microsoft Windows Server 2008 Enterprise R2 x64 SP1
Microsoft Office MS office 2010 Standard Service Pack 1
Login VSI Version 40
Iometer 20060727
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
21 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
533 Virtual desktop user experience Login VSI Analyzer was also used to gather metrics on the user experience at the virtual desktop layer to
ensure that all the desktops had acceptable levels of application performance Login VSI uses the VSImax
parameter to determine the maximum number of sessions that can be obtained from a deployed solution
The calculation methodology used in VSImax is available here
httpwwwloginvsicomdocumentationindexphptitle=Analyzing_Results
534 Test configuration A single virtual desktop pool was configured by using the VMware Horizon View Administrator interface
Each pool was built from a Windows 7 base image The Windows 7 configuration information is available
in Section 46
Desktop pool properties
Automatic Desktop Pool
Users are assigned using Floating assignments
View Storage Accelerator is enabled for all hosts with a refresh period of seven days
800 desktops were deployed across eight hosts (100 desktops a host)
Replica images were stored on a separate volume
22 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
6 Test results and analysis This section presents the results from the different Horizon View VDI characterization tests and the key
findings from each test The testing was focused on the high IOPS workload profile
61 Test scenarios The following tests were conducted to gather results and analysis on the solution stack
1 Boot storm Boot storms represent the worst-case scenario where many virtual desktops are
turned on at the same time and they all contend for the system resources simultaneously This test
was used to evaluate if the storage array hosting the desktops was capable of handling huge
variation in storage IO without causing significant impact on other services
2 Login storm Login storms also represent a high IOPS situation where many users are logging in to
their virtual desktops at the beginning of a workday or a shift In this test all the desktops were
pre-booted and left in an idle state for more than 20 minutes to let their IO settle before running
the Login VSI Medium workload to simulate users logging in to their virtual desktops
3 Steady state workload for standard users with normal IOPS After the login storm for the previous
test was completed the Login VSI Medium workload was allowed to run for at least one hour to
simulate the real-world scenario of users performing their daily tasks The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
4 Steady state workload for users with high IOPS The previous test was repeated with the Login
VSI Medium workload and Iometer scripts in desktop VMs as described in Section 521 to simulate
real-world heavy users performing their daily tasks with high IOPS The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
The following sections provide results from the boot storm login storm and steady state testing for the
Fluid Cache for SAN based VDI solution
23 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
62 Boot storm IO To simulate a boot storm the virtual desktops were reset simultaneously from the VMware vSphere client
Figure 6 shows the IO pattern on the Fluid Cache for the boot storm
Figure 6 SAN HQ data showing boot storm performance with Fluid Cache array
With 800 desktops the boot storm generated about 115000 total IOPS with a majority of them being
write operations All desktops were available for use in less than four minutes
24 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
63 Login storm and steady state for standard users (LoginVSI
Medium) Login VSI was programmed to start 800 virtual desktops over a period of about 60 minutes after pre-
booting the virtual desktops The peak IOPS during the login storm observed by the vSphere servers
hosting the desktops was about 6500 IOPS (8ndash10 IOPS a VM)
In a standard user environment login storms generate significantly more write IOPS than a boot storm or
steady state because of multiple factors such as
User profile activity
Starting operating system services on the desktop
First start of applications
After a virtual desktop has achieved a steady state after user login the Windows 7 OS has cached
applications in memory and does not need to access storage each time the application is started This
leads to lesser IOPS during the steady state Figure 7 here shows the various IO characteristics during the
login storm and steady state of these tests
25 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 7 IOPS and Cache Hit for the standard user test
On the Fluid Cache layer the maximum IOPS reached 6500 with cache-hit reaching 100 percent and
read-hit around 95 percent As shown in the Figure 8 here the throughput peaked at 98 MBps with a low
latency of less than 2 msec
26 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 8 Throughput and Latency for the standard user test
631 Server host performance During the login storm and steady state of the test the vSphere host CPU memory network and storage
performance were measured on all the servers that hosted the virtual desktops The performance of one
such vSphere server is given here The other vSphere servers had similar performance characteristics
Statistics for the vSphere hosts were captured by using VMware vCenter Server The figures here show the
CPU memory and network utilization for boot storm login storm and steady state of one of the vSphere
servers hosting the virtual desktops The results shown here are for a test run with 800 no standard user
desktops in the desktop pool
27 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 9 Average CPU performance per core on one vSphere host during login storm and steady state
Figure 10 Disk space usage during login storm and steady state
0
10
20
30
40
50
60
70
80
90
100
1020 1045 1110 1135 1200 1225
Per
cen
t
Time
CPU Performance
0
50
100
150
200
250
300
1020 1040 1100 1120 1140 1200 1220
GB
Time
Memory Performance
Granted Swap used Shared common
28 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 11 Overall network performance during login storm and steady state
Figure 12 Storage adapter performance during login storm and steady state
0
10000
20000
30000
40000
50000
60000
70000
1020 1045 1110 1135 1200 1225
kBp
s
Time
Network Performance
0
05
1
15
2
25
1020 1045 1110 1135 1200 1225
mSe
c
Time
Storage adaptor performance
29 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
The key observations from the statistics were
CPU utilization was less than the 85 percent threshold throughout the test
Active disk space usage was about 80 percent during the boost storm and about 60 percent
during login storm and steady state There was minimal-or no memory ballooning observed
Network utilization was about 45 percent which included all the networks such as iSCSI SAN VDI
LAN Management LAN and vMotion LAN
Average read- and write latencies at the storage adapter level were very close to the observed
latencies in Fluid Cache 2 msec
632 Monitoring user experience Figure 13 here shows the response time as experienced by each user as calculated by Login VSI The graph
clearly shows that the VSImax (Dynamic) value has not been reached and there were non-responsive or
inactive sessions This means that the array is capable of supporting the 1000 desktops and all users have
acceptable response times for applications that the user is has started
Figure 13 Login VSI user experience monitoring for 800 standard user desktops
30 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
633 Standard user test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SANndashbased VDI solution is able to host 800 virtual desktops and support
a standard user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only operations and
less than 2 percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to handle this login storm easily with low latency mdash it delivered the required 6500 IOPS with less
than 2 milliseconds of write latency with a 99 percent write VDI IO workload
64 Login storm and steady state with high IOPS (LoginVSI Medium +
Iometer) As mentioned earlier Iometer was used in desktop VMs alongside the Login VSI Medium workload to
simulate high IOPS type of VDI environment To mimic actual VDI workload profile the following Iometer
profile was used
20 KB block size 80 percent write 75 percent random with 25 msec burst delay
Figure 14 here shows the various IO characteristics during the login storm and steady state of these tests
Figure 14 IOPS and Cache Hit for the high IOPS test
On the Fluid Cache layer the maximum IOPS reached was approximately 72000 (or 90 IOPSVM) with
cache write-hit 100 percent and read-hit around 95 percent As shown in the Figure 15 the throughput
peaked at greater than 900 MBps with a peak latency of approximately 75 msec
31 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 15 Throughput and Latency for the high IOPS test
32 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
641 Server host performance Similar to the standard user test statistics for the vSphere hosts were captured by using VMware vCenter
Server during the high IOPS (heavy user) test also There are no significant differences in CPU disk space
and network utilization between standard users and heavy users The storage adapter latency is also
showing similar on hosts and observed on Fluid Cache
642 User experience monitoring Figure 16 here shows the response time as experienced by each user as calculated by Login VSI for the
heavy user test The graph shows that the VSImax (Dynamic) value was 796 indicating that the solution is
capable of supporting the 800 user high IOPS desktops with 90 IOPSVM
Figure 16 Login VSI user experience monitoring for 800 user high IOPS desktops
33 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
643 High IOPS (heavy user) test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SAN based VDI solution is able to host 800 virtual desktops and support a
high user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only and less than 2
percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to easily handle this login storm with low latency Subsequently it was able to handle 72000 IOPS
at high IOPS steady state with 90 IOPSVM with a maximum of 75 msec latency
34 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
7 Best practices This section provides the best practices derived from the testing and analysis in Section 6
71 Virtual Desktop Infrastructure This section provides best practices for the implementation of VDI using Dell Fluid Cache for SAN
711 Implement roaming profiles and folder redirection Dell recommends that all users in the VDI environment be configured with roaming profiles and folder
redirection This preserves user profiles and user data across boots while using non-persistent virtual
desktops
Also Dell recommends to use a high performance file service to provide the profile and folder redirection
A separate array may be used to host these volumes for best performance
712 Boot and login storm considerations Section 62 demonstrated the Fluid Cache for SAN performance under boot storm To avoid any potential
IO bursts because of boot storm and degraded user experience and performances Dell recommends that
all or portion of desktops be prebooted Connection brokers such as VMware Horizon View provide the
functionality to configure number of standby desktops
713 Windows 7 master image for desktop VMs Dell recommends that the operating system be customized in order to provide the best performance in a
VDI environment This includes disabling some services which may not be required This can improve
performance for the end user VMware has a specific set of recommendations and settings for Windows 7
and Windows 8 that allow for faster logins quicker screen refreshes and generally better performance
The VMware recommendations for Windows 7 and Windows 8 image optimization can be found here
httpwwwvmwarecomresourcestechresources10157
714 VDI Management infrastructure recommendations Dell recommends to have redundancy and load balancing for all VDI management services in the case of
VMware Horizon View solution as tested here the vSphere Server VMware Horizon View Servers and SQL
Servers Ideally these should be running on clustered hosts with VMware vSphere DRS (distributed
resource scheduler) and HA (high availability) enabled
72 Server host The vSphere servers hosting the infrastructure service providers and the virtual desktops are
recommended to be configured as follows
35 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Follow VMware and Dell best practices for installing and configuring vSphere
Separate virtual switches to segregate iSCSI SAN traffic VDI traffic vMotion traffic and Management
network traffic
Each network path must be assigned to a minimum of two physical NICs for high availability
VMware Knowledge Base article about best practices for installing vSphere 55
httpkbvmwarecomkb2052329
73 Network layer Dell recommends that at least two physical NICs on each vSphere server be dedicated to the VDI network
Use VLANs to segregate different types of network traffic on the same physical network In this case Dell
recommends to separate the infrastructure vMotion and VDI LAN traffic in to separate VLANs
Do not use VLANs to segregate iSCSI SAN and Fluide Cache traffic It is required that SAN and Cache traffic
be on separate dedicated physical network to provide the best performance
Virtual switches in vSphere have a default limit of 120 ports If the number of virtual desktops on each host
exceeds the available ports vSwitch properties should be changed to support the required number of
virtual desktops This change requires a restart of the host vSphere server
On iSCSI SAN switches Spanning tree must be disabled on switch ports connected to end devices for
server and storage ports The PortFast setting must be enabled in the switch configuration for these ports
Jumbo frames and Flow control (if the NICs support it) should be enabled for all components of the iSCSI
network
More information about configuring Dell Networking switches for use with Dell Storage iSCSI SANs is
available here
httpencommunitydellcomtechcenterstoragewwiki4250switch-configuration-guides-by-sisaspx
74 Storage The Dell SC storage arrays combined with Fluid Cache is an excellent platform for providing cost-effective
performance in VDI environments
Fluid Cache for SAN extends the power of Compellent intelligent data placement from the SAN to the
server By providing a single infrastructure for data at both high- and low ends of the performance
spectrum Fluid Cache for SAN with Storage Center 65 array software eliminates the tradeoffs between
server performance and full-featured SAN benefits such as reliability manageability and data protection
Dell recommends to have separate volumes for base image and virtual desktops This enables better
manageability of the volumes easier performance monitoring and allows easy future growth
Dell recommends to use a separate high performance file service to provide file shares for roaming
profiles and user shares
36 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
8 Conclusion The technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed by using a Horizon View VDI platform leveraging Dell Fluid Cache for SAN The storage IO
characteristics under various VDI workload scenarios (boot storm login storm and steady state) along
with performance characteristics throughout the VDI stack (for example vSphere server performance and
user experience) demonstrate the optimal configuration of the infrastructure used for this VDI
deployment For more information about Fluid Cache contact your Dell account manager
37 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
A Horizon view solution configuration
Table 7 Hardware components
Hardware components Description
Virtual Desktops 4 timesDell PowerEdge R720 Servers (Fluid Cache Providers)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
2times350 GB Dell Express Flash PCIe SSDs
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
4 x Dell PowerEdge R720 Servers (Fluid Cache Clients)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55 U2 on all R720 servers Windows 7 (64 Bit) VMs
Infrastructure Servers 2 x Dell PowerEdge R720 servers
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
96 GB RAM
2times300 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55U2 on all R720 servers VMs are loaded with Microsoft Windows 2008 R2
Active Directory
VMware Horizon View 60 Server 1
VMware Horizon View 60 Server 2
VMware vCenter Server 55 update 2
VMware Horizon View Composer
SQL Server
File Server
Login VSI Launchers 8 x Dell PowerEdge M610 servers
2timesIntelreg Xeonreg E-5503 200 GHz Processors
16 GB RAM
4times146 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57711 10GbE NIC
ESXi 51 installed on all R810 servers VMs are loaded with Microsoft Windows 7 64bit Each VM supports up to 30 Login VSI launcher sessions
38 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Network Management VDI LAN
1timesDell Force10 S55 1Gb Ethernet Switch
iSCSI SAN
1timesDell Force10 S4810 10Gb Ethernet Switch
Cache network
1timesDell Force10 S4810 10Gb Ethernet Switch
One Force10 S4810 switch might suffice for all the cache iSCSI SAN VDI LAN and management traffic
Storage 2timesDell Compellent SC8000 controllers 4times6Gb SAS 4-port PCI-E Full-height cards for back-end connectivity 2times10Gb iSCSI 2 port PCI-E Low-profile IO cards for front end connectivity 1timesDell Compellent SC200 disk enclosures 12times4TB NL-SAS 6Gb 72K 35rdquo drives
User Data Infrastructure VMs Virtual Desktops
Performance Monitoring
Dell Compellent Enterprise Manager Dell Fluid Cache for SAN performance monitoring tool () vCenter Performance monitoring Liquidware Stratusphere UX
Performance monitoring on Compellent arrays Fluid Cache performance monitoring Performance monitoring and capture at the ESXi host User experience monitoring on the virtual desktop
39 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 8 Software components
Software components Description Version
Dell Fluid Cache for SAN 20
Dell Compellent Storage Center 64
Dell Compellent Enterprise Manager 64
VMware Horizon View Server 60
VMware Horizon View Composer 60
VMware Horizon View Agent 60
VMware Horizon View Client 64-bit 60
VMware ESXi Hypervisor 55 U2
VMware vCenter Server 55 U2
Microsoft SQL Server 2008R2 Enterprise x64 105016001
Client VM OS Microsoft Windows 7 Enterprise x64 SP1
Management VM OS Microsoft Windows Server 2008 Enterprise R2 x64 SP1
Microsoft Office MS office 2010 Standard Service Pack 1
Login VSI Version 40
Iometer 20060727
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
22 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
6 Test results and analysis This section presents the results from the different Horizon View VDI characterization tests and the key
findings from each test The testing was focused on the high IOPS workload profile
61 Test scenarios The following tests were conducted to gather results and analysis on the solution stack
1 Boot storm Boot storms represent the worst-case scenario where many virtual desktops are
turned on at the same time and they all contend for the system resources simultaneously This test
was used to evaluate if the storage array hosting the desktops was capable of handling huge
variation in storage IO without causing significant impact on other services
2 Login storm Login storms also represent a high IOPS situation where many users are logging in to
their virtual desktops at the beginning of a workday or a shift In this test all the desktops were
pre-booted and left in an idle state for more than 20 minutes to let their IO settle before running
the Login VSI Medium workload to simulate users logging in to their virtual desktops
3 Steady state workload for standard users with normal IOPS After the login storm for the previous
test was completed the Login VSI Medium workload was allowed to run for at least one hour to
simulate the real-world scenario of users performing their daily tasks The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
4 Steady state workload for users with high IOPS The previous test was repeated with the Login
VSI Medium workload and Iometer scripts in desktop VMs as described in Section 521 to simulate
real-world heavy users performing their daily tasks with high IOPS The VSImax (Dynamic)
parameter from Login VSI is used to evaluate the end-user experience of simulated users working
on their virtual desktops throughout these tests
The following sections provide results from the boot storm login storm and steady state testing for the
Fluid Cache for SAN based VDI solution
23 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
62 Boot storm IO To simulate a boot storm the virtual desktops were reset simultaneously from the VMware vSphere client
Figure 6 shows the IO pattern on the Fluid Cache for the boot storm
Figure 6 SAN HQ data showing boot storm performance with Fluid Cache array
With 800 desktops the boot storm generated about 115000 total IOPS with a majority of them being
write operations All desktops were available for use in less than four minutes
24 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
63 Login storm and steady state for standard users (LoginVSI
Medium) Login VSI was programmed to start 800 virtual desktops over a period of about 60 minutes after pre-
booting the virtual desktops The peak IOPS during the login storm observed by the vSphere servers
hosting the desktops was about 6500 IOPS (8ndash10 IOPS a VM)
In a standard user environment login storms generate significantly more write IOPS than a boot storm or
steady state because of multiple factors such as
User profile activity
Starting operating system services on the desktop
First start of applications
After a virtual desktop has achieved a steady state after user login the Windows 7 OS has cached
applications in memory and does not need to access storage each time the application is started This
leads to lesser IOPS during the steady state Figure 7 here shows the various IO characteristics during the
login storm and steady state of these tests
25 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 7 IOPS and Cache Hit for the standard user test
On the Fluid Cache layer the maximum IOPS reached 6500 with cache-hit reaching 100 percent and
read-hit around 95 percent As shown in the Figure 8 here the throughput peaked at 98 MBps with a low
latency of less than 2 msec
26 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 8 Throughput and Latency for the standard user test
631 Server host performance During the login storm and steady state of the test the vSphere host CPU memory network and storage
performance were measured on all the servers that hosted the virtual desktops The performance of one
such vSphere server is given here The other vSphere servers had similar performance characteristics
Statistics for the vSphere hosts were captured by using VMware vCenter Server The figures here show the
CPU memory and network utilization for boot storm login storm and steady state of one of the vSphere
servers hosting the virtual desktops The results shown here are for a test run with 800 no standard user
desktops in the desktop pool
27 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 9 Average CPU performance per core on one vSphere host during login storm and steady state
Figure 10 Disk space usage during login storm and steady state
0
10
20
30
40
50
60
70
80
90
100
1020 1045 1110 1135 1200 1225
Per
cen
t
Time
CPU Performance
0
50
100
150
200
250
300
1020 1040 1100 1120 1140 1200 1220
GB
Time
Memory Performance
Granted Swap used Shared common
28 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 11 Overall network performance during login storm and steady state
Figure 12 Storage adapter performance during login storm and steady state
0
10000
20000
30000
40000
50000
60000
70000
1020 1045 1110 1135 1200 1225
kBp
s
Time
Network Performance
0
05
1
15
2
25
1020 1045 1110 1135 1200 1225
mSe
c
Time
Storage adaptor performance
29 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
The key observations from the statistics were
CPU utilization was less than the 85 percent threshold throughout the test
Active disk space usage was about 80 percent during the boost storm and about 60 percent
during login storm and steady state There was minimal-or no memory ballooning observed
Network utilization was about 45 percent which included all the networks such as iSCSI SAN VDI
LAN Management LAN and vMotion LAN
Average read- and write latencies at the storage adapter level were very close to the observed
latencies in Fluid Cache 2 msec
632 Monitoring user experience Figure 13 here shows the response time as experienced by each user as calculated by Login VSI The graph
clearly shows that the VSImax (Dynamic) value has not been reached and there were non-responsive or
inactive sessions This means that the array is capable of supporting the 1000 desktops and all users have
acceptable response times for applications that the user is has started
Figure 13 Login VSI user experience monitoring for 800 standard user desktops
30 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
633 Standard user test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SANndashbased VDI solution is able to host 800 virtual desktops and support
a standard user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only operations and
less than 2 percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to handle this login storm easily with low latency mdash it delivered the required 6500 IOPS with less
than 2 milliseconds of write latency with a 99 percent write VDI IO workload
64 Login storm and steady state with high IOPS (LoginVSI Medium +
Iometer) As mentioned earlier Iometer was used in desktop VMs alongside the Login VSI Medium workload to
simulate high IOPS type of VDI environment To mimic actual VDI workload profile the following Iometer
profile was used
20 KB block size 80 percent write 75 percent random with 25 msec burst delay
Figure 14 here shows the various IO characteristics during the login storm and steady state of these tests
Figure 14 IOPS and Cache Hit for the high IOPS test
On the Fluid Cache layer the maximum IOPS reached was approximately 72000 (or 90 IOPSVM) with
cache write-hit 100 percent and read-hit around 95 percent As shown in the Figure 15 the throughput
peaked at greater than 900 MBps with a peak latency of approximately 75 msec
31 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 15 Throughput and Latency for the high IOPS test
32 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
641 Server host performance Similar to the standard user test statistics for the vSphere hosts were captured by using VMware vCenter
Server during the high IOPS (heavy user) test also There are no significant differences in CPU disk space
and network utilization between standard users and heavy users The storage adapter latency is also
showing similar on hosts and observed on Fluid Cache
642 User experience monitoring Figure 16 here shows the response time as experienced by each user as calculated by Login VSI for the
heavy user test The graph shows that the VSImax (Dynamic) value was 796 indicating that the solution is
capable of supporting the 800 user high IOPS desktops with 90 IOPSVM
Figure 16 Login VSI user experience monitoring for 800 user high IOPS desktops
33 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
643 High IOPS (heavy user) test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SAN based VDI solution is able to host 800 virtual desktops and support a
high user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only and less than 2
percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to easily handle this login storm with low latency Subsequently it was able to handle 72000 IOPS
at high IOPS steady state with 90 IOPSVM with a maximum of 75 msec latency
34 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
7 Best practices This section provides the best practices derived from the testing and analysis in Section 6
71 Virtual Desktop Infrastructure This section provides best practices for the implementation of VDI using Dell Fluid Cache for SAN
711 Implement roaming profiles and folder redirection Dell recommends that all users in the VDI environment be configured with roaming profiles and folder
redirection This preserves user profiles and user data across boots while using non-persistent virtual
desktops
Also Dell recommends to use a high performance file service to provide the profile and folder redirection
A separate array may be used to host these volumes for best performance
712 Boot and login storm considerations Section 62 demonstrated the Fluid Cache for SAN performance under boot storm To avoid any potential
IO bursts because of boot storm and degraded user experience and performances Dell recommends that
all or portion of desktops be prebooted Connection brokers such as VMware Horizon View provide the
functionality to configure number of standby desktops
713 Windows 7 master image for desktop VMs Dell recommends that the operating system be customized in order to provide the best performance in a
VDI environment This includes disabling some services which may not be required This can improve
performance for the end user VMware has a specific set of recommendations and settings for Windows 7
and Windows 8 that allow for faster logins quicker screen refreshes and generally better performance
The VMware recommendations for Windows 7 and Windows 8 image optimization can be found here
httpwwwvmwarecomresourcestechresources10157
714 VDI Management infrastructure recommendations Dell recommends to have redundancy and load balancing for all VDI management services in the case of
VMware Horizon View solution as tested here the vSphere Server VMware Horizon View Servers and SQL
Servers Ideally these should be running on clustered hosts with VMware vSphere DRS (distributed
resource scheduler) and HA (high availability) enabled
72 Server host The vSphere servers hosting the infrastructure service providers and the virtual desktops are
recommended to be configured as follows
35 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Follow VMware and Dell best practices for installing and configuring vSphere
Separate virtual switches to segregate iSCSI SAN traffic VDI traffic vMotion traffic and Management
network traffic
Each network path must be assigned to a minimum of two physical NICs for high availability
VMware Knowledge Base article about best practices for installing vSphere 55
httpkbvmwarecomkb2052329
73 Network layer Dell recommends that at least two physical NICs on each vSphere server be dedicated to the VDI network
Use VLANs to segregate different types of network traffic on the same physical network In this case Dell
recommends to separate the infrastructure vMotion and VDI LAN traffic in to separate VLANs
Do not use VLANs to segregate iSCSI SAN and Fluide Cache traffic It is required that SAN and Cache traffic
be on separate dedicated physical network to provide the best performance
Virtual switches in vSphere have a default limit of 120 ports If the number of virtual desktops on each host
exceeds the available ports vSwitch properties should be changed to support the required number of
virtual desktops This change requires a restart of the host vSphere server
On iSCSI SAN switches Spanning tree must be disabled on switch ports connected to end devices for
server and storage ports The PortFast setting must be enabled in the switch configuration for these ports
Jumbo frames and Flow control (if the NICs support it) should be enabled for all components of the iSCSI
network
More information about configuring Dell Networking switches for use with Dell Storage iSCSI SANs is
available here
httpencommunitydellcomtechcenterstoragewwiki4250switch-configuration-guides-by-sisaspx
74 Storage The Dell SC storage arrays combined with Fluid Cache is an excellent platform for providing cost-effective
performance in VDI environments
Fluid Cache for SAN extends the power of Compellent intelligent data placement from the SAN to the
server By providing a single infrastructure for data at both high- and low ends of the performance
spectrum Fluid Cache for SAN with Storage Center 65 array software eliminates the tradeoffs between
server performance and full-featured SAN benefits such as reliability manageability and data protection
Dell recommends to have separate volumes for base image and virtual desktops This enables better
manageability of the volumes easier performance monitoring and allows easy future growth
Dell recommends to use a separate high performance file service to provide file shares for roaming
profiles and user shares
36 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
8 Conclusion The technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed by using a Horizon View VDI platform leveraging Dell Fluid Cache for SAN The storage IO
characteristics under various VDI workload scenarios (boot storm login storm and steady state) along
with performance characteristics throughout the VDI stack (for example vSphere server performance and
user experience) demonstrate the optimal configuration of the infrastructure used for this VDI
deployment For more information about Fluid Cache contact your Dell account manager
37 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
A Horizon view solution configuration
Table 7 Hardware components
Hardware components Description
Virtual Desktops 4 timesDell PowerEdge R720 Servers (Fluid Cache Providers)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
2times350 GB Dell Express Flash PCIe SSDs
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
4 x Dell PowerEdge R720 Servers (Fluid Cache Clients)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55 U2 on all R720 servers Windows 7 (64 Bit) VMs
Infrastructure Servers 2 x Dell PowerEdge R720 servers
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
96 GB RAM
2times300 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55U2 on all R720 servers VMs are loaded with Microsoft Windows 2008 R2
Active Directory
VMware Horizon View 60 Server 1
VMware Horizon View 60 Server 2
VMware vCenter Server 55 update 2
VMware Horizon View Composer
SQL Server
File Server
Login VSI Launchers 8 x Dell PowerEdge M610 servers
2timesIntelreg Xeonreg E-5503 200 GHz Processors
16 GB RAM
4times146 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57711 10GbE NIC
ESXi 51 installed on all R810 servers VMs are loaded with Microsoft Windows 7 64bit Each VM supports up to 30 Login VSI launcher sessions
38 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Network Management VDI LAN
1timesDell Force10 S55 1Gb Ethernet Switch
iSCSI SAN
1timesDell Force10 S4810 10Gb Ethernet Switch
Cache network
1timesDell Force10 S4810 10Gb Ethernet Switch
One Force10 S4810 switch might suffice for all the cache iSCSI SAN VDI LAN and management traffic
Storage 2timesDell Compellent SC8000 controllers 4times6Gb SAS 4-port PCI-E Full-height cards for back-end connectivity 2times10Gb iSCSI 2 port PCI-E Low-profile IO cards for front end connectivity 1timesDell Compellent SC200 disk enclosures 12times4TB NL-SAS 6Gb 72K 35rdquo drives
User Data Infrastructure VMs Virtual Desktops
Performance Monitoring
Dell Compellent Enterprise Manager Dell Fluid Cache for SAN performance monitoring tool () vCenter Performance monitoring Liquidware Stratusphere UX
Performance monitoring on Compellent arrays Fluid Cache performance monitoring Performance monitoring and capture at the ESXi host User experience monitoring on the virtual desktop
39 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 8 Software components
Software components Description Version
Dell Fluid Cache for SAN 20
Dell Compellent Storage Center 64
Dell Compellent Enterprise Manager 64
VMware Horizon View Server 60
VMware Horizon View Composer 60
VMware Horizon View Agent 60
VMware Horizon View Client 64-bit 60
VMware ESXi Hypervisor 55 U2
VMware vCenter Server 55 U2
Microsoft SQL Server 2008R2 Enterprise x64 105016001
Client VM OS Microsoft Windows 7 Enterprise x64 SP1
Management VM OS Microsoft Windows Server 2008 Enterprise R2 x64 SP1
Microsoft Office MS office 2010 Standard Service Pack 1
Login VSI Version 40
Iometer 20060727
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
23 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
62 Boot storm IO To simulate a boot storm the virtual desktops were reset simultaneously from the VMware vSphere client
Figure 6 shows the IO pattern on the Fluid Cache for the boot storm
Figure 6 SAN HQ data showing boot storm performance with Fluid Cache array
With 800 desktops the boot storm generated about 115000 total IOPS with a majority of them being
write operations All desktops were available for use in less than four minutes
24 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
63 Login storm and steady state for standard users (LoginVSI
Medium) Login VSI was programmed to start 800 virtual desktops over a period of about 60 minutes after pre-
booting the virtual desktops The peak IOPS during the login storm observed by the vSphere servers
hosting the desktops was about 6500 IOPS (8ndash10 IOPS a VM)
In a standard user environment login storms generate significantly more write IOPS than a boot storm or
steady state because of multiple factors such as
User profile activity
Starting operating system services on the desktop
First start of applications
After a virtual desktop has achieved a steady state after user login the Windows 7 OS has cached
applications in memory and does not need to access storage each time the application is started This
leads to lesser IOPS during the steady state Figure 7 here shows the various IO characteristics during the
login storm and steady state of these tests
25 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 7 IOPS and Cache Hit for the standard user test
On the Fluid Cache layer the maximum IOPS reached 6500 with cache-hit reaching 100 percent and
read-hit around 95 percent As shown in the Figure 8 here the throughput peaked at 98 MBps with a low
latency of less than 2 msec
26 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 8 Throughput and Latency for the standard user test
631 Server host performance During the login storm and steady state of the test the vSphere host CPU memory network and storage
performance were measured on all the servers that hosted the virtual desktops The performance of one
such vSphere server is given here The other vSphere servers had similar performance characteristics
Statistics for the vSphere hosts were captured by using VMware vCenter Server The figures here show the
CPU memory and network utilization for boot storm login storm and steady state of one of the vSphere
servers hosting the virtual desktops The results shown here are for a test run with 800 no standard user
desktops in the desktop pool
27 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 9 Average CPU performance per core on one vSphere host during login storm and steady state
Figure 10 Disk space usage during login storm and steady state
0
10
20
30
40
50
60
70
80
90
100
1020 1045 1110 1135 1200 1225
Per
cen
t
Time
CPU Performance
0
50
100
150
200
250
300
1020 1040 1100 1120 1140 1200 1220
GB
Time
Memory Performance
Granted Swap used Shared common
28 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 11 Overall network performance during login storm and steady state
Figure 12 Storage adapter performance during login storm and steady state
0
10000
20000
30000
40000
50000
60000
70000
1020 1045 1110 1135 1200 1225
kBp
s
Time
Network Performance
0
05
1
15
2
25
1020 1045 1110 1135 1200 1225
mSe
c
Time
Storage adaptor performance
29 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
The key observations from the statistics were
CPU utilization was less than the 85 percent threshold throughout the test
Active disk space usage was about 80 percent during the boost storm and about 60 percent
during login storm and steady state There was minimal-or no memory ballooning observed
Network utilization was about 45 percent which included all the networks such as iSCSI SAN VDI
LAN Management LAN and vMotion LAN
Average read- and write latencies at the storage adapter level were very close to the observed
latencies in Fluid Cache 2 msec
632 Monitoring user experience Figure 13 here shows the response time as experienced by each user as calculated by Login VSI The graph
clearly shows that the VSImax (Dynamic) value has not been reached and there were non-responsive or
inactive sessions This means that the array is capable of supporting the 1000 desktops and all users have
acceptable response times for applications that the user is has started
Figure 13 Login VSI user experience monitoring for 800 standard user desktops
30 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
633 Standard user test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SANndashbased VDI solution is able to host 800 virtual desktops and support
a standard user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only operations and
less than 2 percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to handle this login storm easily with low latency mdash it delivered the required 6500 IOPS with less
than 2 milliseconds of write latency with a 99 percent write VDI IO workload
64 Login storm and steady state with high IOPS (LoginVSI Medium +
Iometer) As mentioned earlier Iometer was used in desktop VMs alongside the Login VSI Medium workload to
simulate high IOPS type of VDI environment To mimic actual VDI workload profile the following Iometer
profile was used
20 KB block size 80 percent write 75 percent random with 25 msec burst delay
Figure 14 here shows the various IO characteristics during the login storm and steady state of these tests
Figure 14 IOPS and Cache Hit for the high IOPS test
On the Fluid Cache layer the maximum IOPS reached was approximately 72000 (or 90 IOPSVM) with
cache write-hit 100 percent and read-hit around 95 percent As shown in the Figure 15 the throughput
peaked at greater than 900 MBps with a peak latency of approximately 75 msec
31 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 15 Throughput and Latency for the high IOPS test
32 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
641 Server host performance Similar to the standard user test statistics for the vSphere hosts were captured by using VMware vCenter
Server during the high IOPS (heavy user) test also There are no significant differences in CPU disk space
and network utilization between standard users and heavy users The storage adapter latency is also
showing similar on hosts and observed on Fluid Cache
642 User experience monitoring Figure 16 here shows the response time as experienced by each user as calculated by Login VSI for the
heavy user test The graph shows that the VSImax (Dynamic) value was 796 indicating that the solution is
capable of supporting the 800 user high IOPS desktops with 90 IOPSVM
Figure 16 Login VSI user experience monitoring for 800 user high IOPS desktops
33 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
643 High IOPS (heavy user) test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SAN based VDI solution is able to host 800 virtual desktops and support a
high user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only and less than 2
percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to easily handle this login storm with low latency Subsequently it was able to handle 72000 IOPS
at high IOPS steady state with 90 IOPSVM with a maximum of 75 msec latency
34 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
7 Best practices This section provides the best practices derived from the testing and analysis in Section 6
71 Virtual Desktop Infrastructure This section provides best practices for the implementation of VDI using Dell Fluid Cache for SAN
711 Implement roaming profiles and folder redirection Dell recommends that all users in the VDI environment be configured with roaming profiles and folder
redirection This preserves user profiles and user data across boots while using non-persistent virtual
desktops
Also Dell recommends to use a high performance file service to provide the profile and folder redirection
A separate array may be used to host these volumes for best performance
712 Boot and login storm considerations Section 62 demonstrated the Fluid Cache for SAN performance under boot storm To avoid any potential
IO bursts because of boot storm and degraded user experience and performances Dell recommends that
all or portion of desktops be prebooted Connection brokers such as VMware Horizon View provide the
functionality to configure number of standby desktops
713 Windows 7 master image for desktop VMs Dell recommends that the operating system be customized in order to provide the best performance in a
VDI environment This includes disabling some services which may not be required This can improve
performance for the end user VMware has a specific set of recommendations and settings for Windows 7
and Windows 8 that allow for faster logins quicker screen refreshes and generally better performance
The VMware recommendations for Windows 7 and Windows 8 image optimization can be found here
httpwwwvmwarecomresourcestechresources10157
714 VDI Management infrastructure recommendations Dell recommends to have redundancy and load balancing for all VDI management services in the case of
VMware Horizon View solution as tested here the vSphere Server VMware Horizon View Servers and SQL
Servers Ideally these should be running on clustered hosts with VMware vSphere DRS (distributed
resource scheduler) and HA (high availability) enabled
72 Server host The vSphere servers hosting the infrastructure service providers and the virtual desktops are
recommended to be configured as follows
35 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Follow VMware and Dell best practices for installing and configuring vSphere
Separate virtual switches to segregate iSCSI SAN traffic VDI traffic vMotion traffic and Management
network traffic
Each network path must be assigned to a minimum of two physical NICs for high availability
VMware Knowledge Base article about best practices for installing vSphere 55
httpkbvmwarecomkb2052329
73 Network layer Dell recommends that at least two physical NICs on each vSphere server be dedicated to the VDI network
Use VLANs to segregate different types of network traffic on the same physical network In this case Dell
recommends to separate the infrastructure vMotion and VDI LAN traffic in to separate VLANs
Do not use VLANs to segregate iSCSI SAN and Fluide Cache traffic It is required that SAN and Cache traffic
be on separate dedicated physical network to provide the best performance
Virtual switches in vSphere have a default limit of 120 ports If the number of virtual desktops on each host
exceeds the available ports vSwitch properties should be changed to support the required number of
virtual desktops This change requires a restart of the host vSphere server
On iSCSI SAN switches Spanning tree must be disabled on switch ports connected to end devices for
server and storage ports The PortFast setting must be enabled in the switch configuration for these ports
Jumbo frames and Flow control (if the NICs support it) should be enabled for all components of the iSCSI
network
More information about configuring Dell Networking switches for use with Dell Storage iSCSI SANs is
available here
httpencommunitydellcomtechcenterstoragewwiki4250switch-configuration-guides-by-sisaspx
74 Storage The Dell SC storage arrays combined with Fluid Cache is an excellent platform for providing cost-effective
performance in VDI environments
Fluid Cache for SAN extends the power of Compellent intelligent data placement from the SAN to the
server By providing a single infrastructure for data at both high- and low ends of the performance
spectrum Fluid Cache for SAN with Storage Center 65 array software eliminates the tradeoffs between
server performance and full-featured SAN benefits such as reliability manageability and data protection
Dell recommends to have separate volumes for base image and virtual desktops This enables better
manageability of the volumes easier performance monitoring and allows easy future growth
Dell recommends to use a separate high performance file service to provide file shares for roaming
profiles and user shares
36 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
8 Conclusion The technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed by using a Horizon View VDI platform leveraging Dell Fluid Cache for SAN The storage IO
characteristics under various VDI workload scenarios (boot storm login storm and steady state) along
with performance characteristics throughout the VDI stack (for example vSphere server performance and
user experience) demonstrate the optimal configuration of the infrastructure used for this VDI
deployment For more information about Fluid Cache contact your Dell account manager
37 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
A Horizon view solution configuration
Table 7 Hardware components
Hardware components Description
Virtual Desktops 4 timesDell PowerEdge R720 Servers (Fluid Cache Providers)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
2times350 GB Dell Express Flash PCIe SSDs
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
4 x Dell PowerEdge R720 Servers (Fluid Cache Clients)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55 U2 on all R720 servers Windows 7 (64 Bit) VMs
Infrastructure Servers 2 x Dell PowerEdge R720 servers
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
96 GB RAM
2times300 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55U2 on all R720 servers VMs are loaded with Microsoft Windows 2008 R2
Active Directory
VMware Horizon View 60 Server 1
VMware Horizon View 60 Server 2
VMware vCenter Server 55 update 2
VMware Horizon View Composer
SQL Server
File Server
Login VSI Launchers 8 x Dell PowerEdge M610 servers
2timesIntelreg Xeonreg E-5503 200 GHz Processors
16 GB RAM
4times146 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57711 10GbE NIC
ESXi 51 installed on all R810 servers VMs are loaded with Microsoft Windows 7 64bit Each VM supports up to 30 Login VSI launcher sessions
38 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Network Management VDI LAN
1timesDell Force10 S55 1Gb Ethernet Switch
iSCSI SAN
1timesDell Force10 S4810 10Gb Ethernet Switch
Cache network
1timesDell Force10 S4810 10Gb Ethernet Switch
One Force10 S4810 switch might suffice for all the cache iSCSI SAN VDI LAN and management traffic
Storage 2timesDell Compellent SC8000 controllers 4times6Gb SAS 4-port PCI-E Full-height cards for back-end connectivity 2times10Gb iSCSI 2 port PCI-E Low-profile IO cards for front end connectivity 1timesDell Compellent SC200 disk enclosures 12times4TB NL-SAS 6Gb 72K 35rdquo drives
User Data Infrastructure VMs Virtual Desktops
Performance Monitoring
Dell Compellent Enterprise Manager Dell Fluid Cache for SAN performance monitoring tool () vCenter Performance monitoring Liquidware Stratusphere UX
Performance monitoring on Compellent arrays Fluid Cache performance monitoring Performance monitoring and capture at the ESXi host User experience monitoring on the virtual desktop
39 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 8 Software components
Software components Description Version
Dell Fluid Cache for SAN 20
Dell Compellent Storage Center 64
Dell Compellent Enterprise Manager 64
VMware Horizon View Server 60
VMware Horizon View Composer 60
VMware Horizon View Agent 60
VMware Horizon View Client 64-bit 60
VMware ESXi Hypervisor 55 U2
VMware vCenter Server 55 U2
Microsoft SQL Server 2008R2 Enterprise x64 105016001
Client VM OS Microsoft Windows 7 Enterprise x64 SP1
Management VM OS Microsoft Windows Server 2008 Enterprise R2 x64 SP1
Microsoft Office MS office 2010 Standard Service Pack 1
Login VSI Version 40
Iometer 20060727
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
24 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
63 Login storm and steady state for standard users (LoginVSI
Medium) Login VSI was programmed to start 800 virtual desktops over a period of about 60 minutes after pre-
booting the virtual desktops The peak IOPS during the login storm observed by the vSphere servers
hosting the desktops was about 6500 IOPS (8ndash10 IOPS a VM)
In a standard user environment login storms generate significantly more write IOPS than a boot storm or
steady state because of multiple factors such as
User profile activity
Starting operating system services on the desktop
First start of applications
After a virtual desktop has achieved a steady state after user login the Windows 7 OS has cached
applications in memory and does not need to access storage each time the application is started This
leads to lesser IOPS during the steady state Figure 7 here shows the various IO characteristics during the
login storm and steady state of these tests
25 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 7 IOPS and Cache Hit for the standard user test
On the Fluid Cache layer the maximum IOPS reached 6500 with cache-hit reaching 100 percent and
read-hit around 95 percent As shown in the Figure 8 here the throughput peaked at 98 MBps with a low
latency of less than 2 msec
26 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 8 Throughput and Latency for the standard user test
631 Server host performance During the login storm and steady state of the test the vSphere host CPU memory network and storage
performance were measured on all the servers that hosted the virtual desktops The performance of one
such vSphere server is given here The other vSphere servers had similar performance characteristics
Statistics for the vSphere hosts were captured by using VMware vCenter Server The figures here show the
CPU memory and network utilization for boot storm login storm and steady state of one of the vSphere
servers hosting the virtual desktops The results shown here are for a test run with 800 no standard user
desktops in the desktop pool
27 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 9 Average CPU performance per core on one vSphere host during login storm and steady state
Figure 10 Disk space usage during login storm and steady state
0
10
20
30
40
50
60
70
80
90
100
1020 1045 1110 1135 1200 1225
Per
cen
t
Time
CPU Performance
0
50
100
150
200
250
300
1020 1040 1100 1120 1140 1200 1220
GB
Time
Memory Performance
Granted Swap used Shared common
28 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 11 Overall network performance during login storm and steady state
Figure 12 Storage adapter performance during login storm and steady state
0
10000
20000
30000
40000
50000
60000
70000
1020 1045 1110 1135 1200 1225
kBp
s
Time
Network Performance
0
05
1
15
2
25
1020 1045 1110 1135 1200 1225
mSe
c
Time
Storage adaptor performance
29 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
The key observations from the statistics were
CPU utilization was less than the 85 percent threshold throughout the test
Active disk space usage was about 80 percent during the boost storm and about 60 percent
during login storm and steady state There was minimal-or no memory ballooning observed
Network utilization was about 45 percent which included all the networks such as iSCSI SAN VDI
LAN Management LAN and vMotion LAN
Average read- and write latencies at the storage adapter level were very close to the observed
latencies in Fluid Cache 2 msec
632 Monitoring user experience Figure 13 here shows the response time as experienced by each user as calculated by Login VSI The graph
clearly shows that the VSImax (Dynamic) value has not been reached and there were non-responsive or
inactive sessions This means that the array is capable of supporting the 1000 desktops and all users have
acceptable response times for applications that the user is has started
Figure 13 Login VSI user experience monitoring for 800 standard user desktops
30 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
633 Standard user test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SANndashbased VDI solution is able to host 800 virtual desktops and support
a standard user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only operations and
less than 2 percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to handle this login storm easily with low latency mdash it delivered the required 6500 IOPS with less
than 2 milliseconds of write latency with a 99 percent write VDI IO workload
64 Login storm and steady state with high IOPS (LoginVSI Medium +
Iometer) As mentioned earlier Iometer was used in desktop VMs alongside the Login VSI Medium workload to
simulate high IOPS type of VDI environment To mimic actual VDI workload profile the following Iometer
profile was used
20 KB block size 80 percent write 75 percent random with 25 msec burst delay
Figure 14 here shows the various IO characteristics during the login storm and steady state of these tests
Figure 14 IOPS and Cache Hit for the high IOPS test
On the Fluid Cache layer the maximum IOPS reached was approximately 72000 (or 90 IOPSVM) with
cache write-hit 100 percent and read-hit around 95 percent As shown in the Figure 15 the throughput
peaked at greater than 900 MBps with a peak latency of approximately 75 msec
31 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 15 Throughput and Latency for the high IOPS test
32 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
641 Server host performance Similar to the standard user test statistics for the vSphere hosts were captured by using VMware vCenter
Server during the high IOPS (heavy user) test also There are no significant differences in CPU disk space
and network utilization between standard users and heavy users The storage adapter latency is also
showing similar on hosts and observed on Fluid Cache
642 User experience monitoring Figure 16 here shows the response time as experienced by each user as calculated by Login VSI for the
heavy user test The graph shows that the VSImax (Dynamic) value was 796 indicating that the solution is
capable of supporting the 800 user high IOPS desktops with 90 IOPSVM
Figure 16 Login VSI user experience monitoring for 800 user high IOPS desktops
33 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
643 High IOPS (heavy user) test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SAN based VDI solution is able to host 800 virtual desktops and support a
high user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only and less than 2
percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to easily handle this login storm with low latency Subsequently it was able to handle 72000 IOPS
at high IOPS steady state with 90 IOPSVM with a maximum of 75 msec latency
34 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
7 Best practices This section provides the best practices derived from the testing and analysis in Section 6
71 Virtual Desktop Infrastructure This section provides best practices for the implementation of VDI using Dell Fluid Cache for SAN
711 Implement roaming profiles and folder redirection Dell recommends that all users in the VDI environment be configured with roaming profiles and folder
redirection This preserves user profiles and user data across boots while using non-persistent virtual
desktops
Also Dell recommends to use a high performance file service to provide the profile and folder redirection
A separate array may be used to host these volumes for best performance
712 Boot and login storm considerations Section 62 demonstrated the Fluid Cache for SAN performance under boot storm To avoid any potential
IO bursts because of boot storm and degraded user experience and performances Dell recommends that
all or portion of desktops be prebooted Connection brokers such as VMware Horizon View provide the
functionality to configure number of standby desktops
713 Windows 7 master image for desktop VMs Dell recommends that the operating system be customized in order to provide the best performance in a
VDI environment This includes disabling some services which may not be required This can improve
performance for the end user VMware has a specific set of recommendations and settings for Windows 7
and Windows 8 that allow for faster logins quicker screen refreshes and generally better performance
The VMware recommendations for Windows 7 and Windows 8 image optimization can be found here
httpwwwvmwarecomresourcestechresources10157
714 VDI Management infrastructure recommendations Dell recommends to have redundancy and load balancing for all VDI management services in the case of
VMware Horizon View solution as tested here the vSphere Server VMware Horizon View Servers and SQL
Servers Ideally these should be running on clustered hosts with VMware vSphere DRS (distributed
resource scheduler) and HA (high availability) enabled
72 Server host The vSphere servers hosting the infrastructure service providers and the virtual desktops are
recommended to be configured as follows
35 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Follow VMware and Dell best practices for installing and configuring vSphere
Separate virtual switches to segregate iSCSI SAN traffic VDI traffic vMotion traffic and Management
network traffic
Each network path must be assigned to a minimum of two physical NICs for high availability
VMware Knowledge Base article about best practices for installing vSphere 55
httpkbvmwarecomkb2052329
73 Network layer Dell recommends that at least two physical NICs on each vSphere server be dedicated to the VDI network
Use VLANs to segregate different types of network traffic on the same physical network In this case Dell
recommends to separate the infrastructure vMotion and VDI LAN traffic in to separate VLANs
Do not use VLANs to segregate iSCSI SAN and Fluide Cache traffic It is required that SAN and Cache traffic
be on separate dedicated physical network to provide the best performance
Virtual switches in vSphere have a default limit of 120 ports If the number of virtual desktops on each host
exceeds the available ports vSwitch properties should be changed to support the required number of
virtual desktops This change requires a restart of the host vSphere server
On iSCSI SAN switches Spanning tree must be disabled on switch ports connected to end devices for
server and storage ports The PortFast setting must be enabled in the switch configuration for these ports
Jumbo frames and Flow control (if the NICs support it) should be enabled for all components of the iSCSI
network
More information about configuring Dell Networking switches for use with Dell Storage iSCSI SANs is
available here
httpencommunitydellcomtechcenterstoragewwiki4250switch-configuration-guides-by-sisaspx
74 Storage The Dell SC storage arrays combined with Fluid Cache is an excellent platform for providing cost-effective
performance in VDI environments
Fluid Cache for SAN extends the power of Compellent intelligent data placement from the SAN to the
server By providing a single infrastructure for data at both high- and low ends of the performance
spectrum Fluid Cache for SAN with Storage Center 65 array software eliminates the tradeoffs between
server performance and full-featured SAN benefits such as reliability manageability and data protection
Dell recommends to have separate volumes for base image and virtual desktops This enables better
manageability of the volumes easier performance monitoring and allows easy future growth
Dell recommends to use a separate high performance file service to provide file shares for roaming
profiles and user shares
36 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
8 Conclusion The technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed by using a Horizon View VDI platform leveraging Dell Fluid Cache for SAN The storage IO
characteristics under various VDI workload scenarios (boot storm login storm and steady state) along
with performance characteristics throughout the VDI stack (for example vSphere server performance and
user experience) demonstrate the optimal configuration of the infrastructure used for this VDI
deployment For more information about Fluid Cache contact your Dell account manager
37 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
A Horizon view solution configuration
Table 7 Hardware components
Hardware components Description
Virtual Desktops 4 timesDell PowerEdge R720 Servers (Fluid Cache Providers)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
2times350 GB Dell Express Flash PCIe SSDs
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
4 x Dell PowerEdge R720 Servers (Fluid Cache Clients)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55 U2 on all R720 servers Windows 7 (64 Bit) VMs
Infrastructure Servers 2 x Dell PowerEdge R720 servers
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
96 GB RAM
2times300 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55U2 on all R720 servers VMs are loaded with Microsoft Windows 2008 R2
Active Directory
VMware Horizon View 60 Server 1
VMware Horizon View 60 Server 2
VMware vCenter Server 55 update 2
VMware Horizon View Composer
SQL Server
File Server
Login VSI Launchers 8 x Dell PowerEdge M610 servers
2timesIntelreg Xeonreg E-5503 200 GHz Processors
16 GB RAM
4times146 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57711 10GbE NIC
ESXi 51 installed on all R810 servers VMs are loaded with Microsoft Windows 7 64bit Each VM supports up to 30 Login VSI launcher sessions
38 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Network Management VDI LAN
1timesDell Force10 S55 1Gb Ethernet Switch
iSCSI SAN
1timesDell Force10 S4810 10Gb Ethernet Switch
Cache network
1timesDell Force10 S4810 10Gb Ethernet Switch
One Force10 S4810 switch might suffice for all the cache iSCSI SAN VDI LAN and management traffic
Storage 2timesDell Compellent SC8000 controllers 4times6Gb SAS 4-port PCI-E Full-height cards for back-end connectivity 2times10Gb iSCSI 2 port PCI-E Low-profile IO cards for front end connectivity 1timesDell Compellent SC200 disk enclosures 12times4TB NL-SAS 6Gb 72K 35rdquo drives
User Data Infrastructure VMs Virtual Desktops
Performance Monitoring
Dell Compellent Enterprise Manager Dell Fluid Cache for SAN performance monitoring tool () vCenter Performance monitoring Liquidware Stratusphere UX
Performance monitoring on Compellent arrays Fluid Cache performance monitoring Performance monitoring and capture at the ESXi host User experience monitoring on the virtual desktop
39 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 8 Software components
Software components Description Version
Dell Fluid Cache for SAN 20
Dell Compellent Storage Center 64
Dell Compellent Enterprise Manager 64
VMware Horizon View Server 60
VMware Horizon View Composer 60
VMware Horizon View Agent 60
VMware Horizon View Client 64-bit 60
VMware ESXi Hypervisor 55 U2
VMware vCenter Server 55 U2
Microsoft SQL Server 2008R2 Enterprise x64 105016001
Client VM OS Microsoft Windows 7 Enterprise x64 SP1
Management VM OS Microsoft Windows Server 2008 Enterprise R2 x64 SP1
Microsoft Office MS office 2010 Standard Service Pack 1
Login VSI Version 40
Iometer 20060727
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
25 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 7 IOPS and Cache Hit for the standard user test
On the Fluid Cache layer the maximum IOPS reached 6500 with cache-hit reaching 100 percent and
read-hit around 95 percent As shown in the Figure 8 here the throughput peaked at 98 MBps with a low
latency of less than 2 msec
26 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 8 Throughput and Latency for the standard user test
631 Server host performance During the login storm and steady state of the test the vSphere host CPU memory network and storage
performance were measured on all the servers that hosted the virtual desktops The performance of one
such vSphere server is given here The other vSphere servers had similar performance characteristics
Statistics for the vSphere hosts were captured by using VMware vCenter Server The figures here show the
CPU memory and network utilization for boot storm login storm and steady state of one of the vSphere
servers hosting the virtual desktops The results shown here are for a test run with 800 no standard user
desktops in the desktop pool
27 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 9 Average CPU performance per core on one vSphere host during login storm and steady state
Figure 10 Disk space usage during login storm and steady state
0
10
20
30
40
50
60
70
80
90
100
1020 1045 1110 1135 1200 1225
Per
cen
t
Time
CPU Performance
0
50
100
150
200
250
300
1020 1040 1100 1120 1140 1200 1220
GB
Time
Memory Performance
Granted Swap used Shared common
28 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 11 Overall network performance during login storm and steady state
Figure 12 Storage adapter performance during login storm and steady state
0
10000
20000
30000
40000
50000
60000
70000
1020 1045 1110 1135 1200 1225
kBp
s
Time
Network Performance
0
05
1
15
2
25
1020 1045 1110 1135 1200 1225
mSe
c
Time
Storage adaptor performance
29 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
The key observations from the statistics were
CPU utilization was less than the 85 percent threshold throughout the test
Active disk space usage was about 80 percent during the boost storm and about 60 percent
during login storm and steady state There was minimal-or no memory ballooning observed
Network utilization was about 45 percent which included all the networks such as iSCSI SAN VDI
LAN Management LAN and vMotion LAN
Average read- and write latencies at the storage adapter level were very close to the observed
latencies in Fluid Cache 2 msec
632 Monitoring user experience Figure 13 here shows the response time as experienced by each user as calculated by Login VSI The graph
clearly shows that the VSImax (Dynamic) value has not been reached and there were non-responsive or
inactive sessions This means that the array is capable of supporting the 1000 desktops and all users have
acceptable response times for applications that the user is has started
Figure 13 Login VSI user experience monitoring for 800 standard user desktops
30 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
633 Standard user test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SANndashbased VDI solution is able to host 800 virtual desktops and support
a standard user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only operations and
less than 2 percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to handle this login storm easily with low latency mdash it delivered the required 6500 IOPS with less
than 2 milliseconds of write latency with a 99 percent write VDI IO workload
64 Login storm and steady state with high IOPS (LoginVSI Medium +
Iometer) As mentioned earlier Iometer was used in desktop VMs alongside the Login VSI Medium workload to
simulate high IOPS type of VDI environment To mimic actual VDI workload profile the following Iometer
profile was used
20 KB block size 80 percent write 75 percent random with 25 msec burst delay
Figure 14 here shows the various IO characteristics during the login storm and steady state of these tests
Figure 14 IOPS and Cache Hit for the high IOPS test
On the Fluid Cache layer the maximum IOPS reached was approximately 72000 (or 90 IOPSVM) with
cache write-hit 100 percent and read-hit around 95 percent As shown in the Figure 15 the throughput
peaked at greater than 900 MBps with a peak latency of approximately 75 msec
31 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 15 Throughput and Latency for the high IOPS test
32 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
641 Server host performance Similar to the standard user test statistics for the vSphere hosts were captured by using VMware vCenter
Server during the high IOPS (heavy user) test also There are no significant differences in CPU disk space
and network utilization between standard users and heavy users The storage adapter latency is also
showing similar on hosts and observed on Fluid Cache
642 User experience monitoring Figure 16 here shows the response time as experienced by each user as calculated by Login VSI for the
heavy user test The graph shows that the VSImax (Dynamic) value was 796 indicating that the solution is
capable of supporting the 800 user high IOPS desktops with 90 IOPSVM
Figure 16 Login VSI user experience monitoring for 800 user high IOPS desktops
33 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
643 High IOPS (heavy user) test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SAN based VDI solution is able to host 800 virtual desktops and support a
high user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only and less than 2
percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to easily handle this login storm with low latency Subsequently it was able to handle 72000 IOPS
at high IOPS steady state with 90 IOPSVM with a maximum of 75 msec latency
34 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
7 Best practices This section provides the best practices derived from the testing and analysis in Section 6
71 Virtual Desktop Infrastructure This section provides best practices for the implementation of VDI using Dell Fluid Cache for SAN
711 Implement roaming profiles and folder redirection Dell recommends that all users in the VDI environment be configured with roaming profiles and folder
redirection This preserves user profiles and user data across boots while using non-persistent virtual
desktops
Also Dell recommends to use a high performance file service to provide the profile and folder redirection
A separate array may be used to host these volumes for best performance
712 Boot and login storm considerations Section 62 demonstrated the Fluid Cache for SAN performance under boot storm To avoid any potential
IO bursts because of boot storm and degraded user experience and performances Dell recommends that
all or portion of desktops be prebooted Connection brokers such as VMware Horizon View provide the
functionality to configure number of standby desktops
713 Windows 7 master image for desktop VMs Dell recommends that the operating system be customized in order to provide the best performance in a
VDI environment This includes disabling some services which may not be required This can improve
performance for the end user VMware has a specific set of recommendations and settings for Windows 7
and Windows 8 that allow for faster logins quicker screen refreshes and generally better performance
The VMware recommendations for Windows 7 and Windows 8 image optimization can be found here
httpwwwvmwarecomresourcestechresources10157
714 VDI Management infrastructure recommendations Dell recommends to have redundancy and load balancing for all VDI management services in the case of
VMware Horizon View solution as tested here the vSphere Server VMware Horizon View Servers and SQL
Servers Ideally these should be running on clustered hosts with VMware vSphere DRS (distributed
resource scheduler) and HA (high availability) enabled
72 Server host The vSphere servers hosting the infrastructure service providers and the virtual desktops are
recommended to be configured as follows
35 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Follow VMware and Dell best practices for installing and configuring vSphere
Separate virtual switches to segregate iSCSI SAN traffic VDI traffic vMotion traffic and Management
network traffic
Each network path must be assigned to a minimum of two physical NICs for high availability
VMware Knowledge Base article about best practices for installing vSphere 55
httpkbvmwarecomkb2052329
73 Network layer Dell recommends that at least two physical NICs on each vSphere server be dedicated to the VDI network
Use VLANs to segregate different types of network traffic on the same physical network In this case Dell
recommends to separate the infrastructure vMotion and VDI LAN traffic in to separate VLANs
Do not use VLANs to segregate iSCSI SAN and Fluide Cache traffic It is required that SAN and Cache traffic
be on separate dedicated physical network to provide the best performance
Virtual switches in vSphere have a default limit of 120 ports If the number of virtual desktops on each host
exceeds the available ports vSwitch properties should be changed to support the required number of
virtual desktops This change requires a restart of the host vSphere server
On iSCSI SAN switches Spanning tree must be disabled on switch ports connected to end devices for
server and storage ports The PortFast setting must be enabled in the switch configuration for these ports
Jumbo frames and Flow control (if the NICs support it) should be enabled for all components of the iSCSI
network
More information about configuring Dell Networking switches for use with Dell Storage iSCSI SANs is
available here
httpencommunitydellcomtechcenterstoragewwiki4250switch-configuration-guides-by-sisaspx
74 Storage The Dell SC storage arrays combined with Fluid Cache is an excellent platform for providing cost-effective
performance in VDI environments
Fluid Cache for SAN extends the power of Compellent intelligent data placement from the SAN to the
server By providing a single infrastructure for data at both high- and low ends of the performance
spectrum Fluid Cache for SAN with Storage Center 65 array software eliminates the tradeoffs between
server performance and full-featured SAN benefits such as reliability manageability and data protection
Dell recommends to have separate volumes for base image and virtual desktops This enables better
manageability of the volumes easier performance monitoring and allows easy future growth
Dell recommends to use a separate high performance file service to provide file shares for roaming
profiles and user shares
36 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
8 Conclusion The technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed by using a Horizon View VDI platform leveraging Dell Fluid Cache for SAN The storage IO
characteristics under various VDI workload scenarios (boot storm login storm and steady state) along
with performance characteristics throughout the VDI stack (for example vSphere server performance and
user experience) demonstrate the optimal configuration of the infrastructure used for this VDI
deployment For more information about Fluid Cache contact your Dell account manager
37 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
A Horizon view solution configuration
Table 7 Hardware components
Hardware components Description
Virtual Desktops 4 timesDell PowerEdge R720 Servers (Fluid Cache Providers)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
2times350 GB Dell Express Flash PCIe SSDs
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
4 x Dell PowerEdge R720 Servers (Fluid Cache Clients)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55 U2 on all R720 servers Windows 7 (64 Bit) VMs
Infrastructure Servers 2 x Dell PowerEdge R720 servers
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
96 GB RAM
2times300 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55U2 on all R720 servers VMs are loaded with Microsoft Windows 2008 R2
Active Directory
VMware Horizon View 60 Server 1
VMware Horizon View 60 Server 2
VMware vCenter Server 55 update 2
VMware Horizon View Composer
SQL Server
File Server
Login VSI Launchers 8 x Dell PowerEdge M610 servers
2timesIntelreg Xeonreg E-5503 200 GHz Processors
16 GB RAM
4times146 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57711 10GbE NIC
ESXi 51 installed on all R810 servers VMs are loaded with Microsoft Windows 7 64bit Each VM supports up to 30 Login VSI launcher sessions
38 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Network Management VDI LAN
1timesDell Force10 S55 1Gb Ethernet Switch
iSCSI SAN
1timesDell Force10 S4810 10Gb Ethernet Switch
Cache network
1timesDell Force10 S4810 10Gb Ethernet Switch
One Force10 S4810 switch might suffice for all the cache iSCSI SAN VDI LAN and management traffic
Storage 2timesDell Compellent SC8000 controllers 4times6Gb SAS 4-port PCI-E Full-height cards for back-end connectivity 2times10Gb iSCSI 2 port PCI-E Low-profile IO cards for front end connectivity 1timesDell Compellent SC200 disk enclosures 12times4TB NL-SAS 6Gb 72K 35rdquo drives
User Data Infrastructure VMs Virtual Desktops
Performance Monitoring
Dell Compellent Enterprise Manager Dell Fluid Cache for SAN performance monitoring tool () vCenter Performance monitoring Liquidware Stratusphere UX
Performance monitoring on Compellent arrays Fluid Cache performance monitoring Performance monitoring and capture at the ESXi host User experience monitoring on the virtual desktop
39 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 8 Software components
Software components Description Version
Dell Fluid Cache for SAN 20
Dell Compellent Storage Center 64
Dell Compellent Enterprise Manager 64
VMware Horizon View Server 60
VMware Horizon View Composer 60
VMware Horizon View Agent 60
VMware Horizon View Client 64-bit 60
VMware ESXi Hypervisor 55 U2
VMware vCenter Server 55 U2
Microsoft SQL Server 2008R2 Enterprise x64 105016001
Client VM OS Microsoft Windows 7 Enterprise x64 SP1
Management VM OS Microsoft Windows Server 2008 Enterprise R2 x64 SP1
Microsoft Office MS office 2010 Standard Service Pack 1
Login VSI Version 40
Iometer 20060727
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
26 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 8 Throughput and Latency for the standard user test
631 Server host performance During the login storm and steady state of the test the vSphere host CPU memory network and storage
performance were measured on all the servers that hosted the virtual desktops The performance of one
such vSphere server is given here The other vSphere servers had similar performance characteristics
Statistics for the vSphere hosts were captured by using VMware vCenter Server The figures here show the
CPU memory and network utilization for boot storm login storm and steady state of one of the vSphere
servers hosting the virtual desktops The results shown here are for a test run with 800 no standard user
desktops in the desktop pool
27 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 9 Average CPU performance per core on one vSphere host during login storm and steady state
Figure 10 Disk space usage during login storm and steady state
0
10
20
30
40
50
60
70
80
90
100
1020 1045 1110 1135 1200 1225
Per
cen
t
Time
CPU Performance
0
50
100
150
200
250
300
1020 1040 1100 1120 1140 1200 1220
GB
Time
Memory Performance
Granted Swap used Shared common
28 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 11 Overall network performance during login storm and steady state
Figure 12 Storage adapter performance during login storm and steady state
0
10000
20000
30000
40000
50000
60000
70000
1020 1045 1110 1135 1200 1225
kBp
s
Time
Network Performance
0
05
1
15
2
25
1020 1045 1110 1135 1200 1225
mSe
c
Time
Storage adaptor performance
29 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
The key observations from the statistics were
CPU utilization was less than the 85 percent threshold throughout the test
Active disk space usage was about 80 percent during the boost storm and about 60 percent
during login storm and steady state There was minimal-or no memory ballooning observed
Network utilization was about 45 percent which included all the networks such as iSCSI SAN VDI
LAN Management LAN and vMotion LAN
Average read- and write latencies at the storage adapter level were very close to the observed
latencies in Fluid Cache 2 msec
632 Monitoring user experience Figure 13 here shows the response time as experienced by each user as calculated by Login VSI The graph
clearly shows that the VSImax (Dynamic) value has not been reached and there were non-responsive or
inactive sessions This means that the array is capable of supporting the 1000 desktops and all users have
acceptable response times for applications that the user is has started
Figure 13 Login VSI user experience monitoring for 800 standard user desktops
30 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
633 Standard user test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SANndashbased VDI solution is able to host 800 virtual desktops and support
a standard user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only operations and
less than 2 percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to handle this login storm easily with low latency mdash it delivered the required 6500 IOPS with less
than 2 milliseconds of write latency with a 99 percent write VDI IO workload
64 Login storm and steady state with high IOPS (LoginVSI Medium +
Iometer) As mentioned earlier Iometer was used in desktop VMs alongside the Login VSI Medium workload to
simulate high IOPS type of VDI environment To mimic actual VDI workload profile the following Iometer
profile was used
20 KB block size 80 percent write 75 percent random with 25 msec burst delay
Figure 14 here shows the various IO characteristics during the login storm and steady state of these tests
Figure 14 IOPS and Cache Hit for the high IOPS test
On the Fluid Cache layer the maximum IOPS reached was approximately 72000 (or 90 IOPSVM) with
cache write-hit 100 percent and read-hit around 95 percent As shown in the Figure 15 the throughput
peaked at greater than 900 MBps with a peak latency of approximately 75 msec
31 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 15 Throughput and Latency for the high IOPS test
32 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
641 Server host performance Similar to the standard user test statistics for the vSphere hosts were captured by using VMware vCenter
Server during the high IOPS (heavy user) test also There are no significant differences in CPU disk space
and network utilization between standard users and heavy users The storage adapter latency is also
showing similar on hosts and observed on Fluid Cache
642 User experience monitoring Figure 16 here shows the response time as experienced by each user as calculated by Login VSI for the
heavy user test The graph shows that the VSImax (Dynamic) value was 796 indicating that the solution is
capable of supporting the 800 user high IOPS desktops with 90 IOPSVM
Figure 16 Login VSI user experience monitoring for 800 user high IOPS desktops
33 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
643 High IOPS (heavy user) test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SAN based VDI solution is able to host 800 virtual desktops and support a
high user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only and less than 2
percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to easily handle this login storm with low latency Subsequently it was able to handle 72000 IOPS
at high IOPS steady state with 90 IOPSVM with a maximum of 75 msec latency
34 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
7 Best practices This section provides the best practices derived from the testing and analysis in Section 6
71 Virtual Desktop Infrastructure This section provides best practices for the implementation of VDI using Dell Fluid Cache for SAN
711 Implement roaming profiles and folder redirection Dell recommends that all users in the VDI environment be configured with roaming profiles and folder
redirection This preserves user profiles and user data across boots while using non-persistent virtual
desktops
Also Dell recommends to use a high performance file service to provide the profile and folder redirection
A separate array may be used to host these volumes for best performance
712 Boot and login storm considerations Section 62 demonstrated the Fluid Cache for SAN performance under boot storm To avoid any potential
IO bursts because of boot storm and degraded user experience and performances Dell recommends that
all or portion of desktops be prebooted Connection brokers such as VMware Horizon View provide the
functionality to configure number of standby desktops
713 Windows 7 master image for desktop VMs Dell recommends that the operating system be customized in order to provide the best performance in a
VDI environment This includes disabling some services which may not be required This can improve
performance for the end user VMware has a specific set of recommendations and settings for Windows 7
and Windows 8 that allow for faster logins quicker screen refreshes and generally better performance
The VMware recommendations for Windows 7 and Windows 8 image optimization can be found here
httpwwwvmwarecomresourcestechresources10157
714 VDI Management infrastructure recommendations Dell recommends to have redundancy and load balancing for all VDI management services in the case of
VMware Horizon View solution as tested here the vSphere Server VMware Horizon View Servers and SQL
Servers Ideally these should be running on clustered hosts with VMware vSphere DRS (distributed
resource scheduler) and HA (high availability) enabled
72 Server host The vSphere servers hosting the infrastructure service providers and the virtual desktops are
recommended to be configured as follows
35 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Follow VMware and Dell best practices for installing and configuring vSphere
Separate virtual switches to segregate iSCSI SAN traffic VDI traffic vMotion traffic and Management
network traffic
Each network path must be assigned to a minimum of two physical NICs for high availability
VMware Knowledge Base article about best practices for installing vSphere 55
httpkbvmwarecomkb2052329
73 Network layer Dell recommends that at least two physical NICs on each vSphere server be dedicated to the VDI network
Use VLANs to segregate different types of network traffic on the same physical network In this case Dell
recommends to separate the infrastructure vMotion and VDI LAN traffic in to separate VLANs
Do not use VLANs to segregate iSCSI SAN and Fluide Cache traffic It is required that SAN and Cache traffic
be on separate dedicated physical network to provide the best performance
Virtual switches in vSphere have a default limit of 120 ports If the number of virtual desktops on each host
exceeds the available ports vSwitch properties should be changed to support the required number of
virtual desktops This change requires a restart of the host vSphere server
On iSCSI SAN switches Spanning tree must be disabled on switch ports connected to end devices for
server and storage ports The PortFast setting must be enabled in the switch configuration for these ports
Jumbo frames and Flow control (if the NICs support it) should be enabled for all components of the iSCSI
network
More information about configuring Dell Networking switches for use with Dell Storage iSCSI SANs is
available here
httpencommunitydellcomtechcenterstoragewwiki4250switch-configuration-guides-by-sisaspx
74 Storage The Dell SC storage arrays combined with Fluid Cache is an excellent platform for providing cost-effective
performance in VDI environments
Fluid Cache for SAN extends the power of Compellent intelligent data placement from the SAN to the
server By providing a single infrastructure for data at both high- and low ends of the performance
spectrum Fluid Cache for SAN with Storage Center 65 array software eliminates the tradeoffs between
server performance and full-featured SAN benefits such as reliability manageability and data protection
Dell recommends to have separate volumes for base image and virtual desktops This enables better
manageability of the volumes easier performance monitoring and allows easy future growth
Dell recommends to use a separate high performance file service to provide file shares for roaming
profiles and user shares
36 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
8 Conclusion The technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed by using a Horizon View VDI platform leveraging Dell Fluid Cache for SAN The storage IO
characteristics under various VDI workload scenarios (boot storm login storm and steady state) along
with performance characteristics throughout the VDI stack (for example vSphere server performance and
user experience) demonstrate the optimal configuration of the infrastructure used for this VDI
deployment For more information about Fluid Cache contact your Dell account manager
37 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
A Horizon view solution configuration
Table 7 Hardware components
Hardware components Description
Virtual Desktops 4 timesDell PowerEdge R720 Servers (Fluid Cache Providers)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
2times350 GB Dell Express Flash PCIe SSDs
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
4 x Dell PowerEdge R720 Servers (Fluid Cache Clients)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55 U2 on all R720 servers Windows 7 (64 Bit) VMs
Infrastructure Servers 2 x Dell PowerEdge R720 servers
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
96 GB RAM
2times300 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55U2 on all R720 servers VMs are loaded with Microsoft Windows 2008 R2
Active Directory
VMware Horizon View 60 Server 1
VMware Horizon View 60 Server 2
VMware vCenter Server 55 update 2
VMware Horizon View Composer
SQL Server
File Server
Login VSI Launchers 8 x Dell PowerEdge M610 servers
2timesIntelreg Xeonreg E-5503 200 GHz Processors
16 GB RAM
4times146 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57711 10GbE NIC
ESXi 51 installed on all R810 servers VMs are loaded with Microsoft Windows 7 64bit Each VM supports up to 30 Login VSI launcher sessions
38 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Network Management VDI LAN
1timesDell Force10 S55 1Gb Ethernet Switch
iSCSI SAN
1timesDell Force10 S4810 10Gb Ethernet Switch
Cache network
1timesDell Force10 S4810 10Gb Ethernet Switch
One Force10 S4810 switch might suffice for all the cache iSCSI SAN VDI LAN and management traffic
Storage 2timesDell Compellent SC8000 controllers 4times6Gb SAS 4-port PCI-E Full-height cards for back-end connectivity 2times10Gb iSCSI 2 port PCI-E Low-profile IO cards for front end connectivity 1timesDell Compellent SC200 disk enclosures 12times4TB NL-SAS 6Gb 72K 35rdquo drives
User Data Infrastructure VMs Virtual Desktops
Performance Monitoring
Dell Compellent Enterprise Manager Dell Fluid Cache for SAN performance monitoring tool () vCenter Performance monitoring Liquidware Stratusphere UX
Performance monitoring on Compellent arrays Fluid Cache performance monitoring Performance monitoring and capture at the ESXi host User experience monitoring on the virtual desktop
39 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 8 Software components
Software components Description Version
Dell Fluid Cache for SAN 20
Dell Compellent Storage Center 64
Dell Compellent Enterprise Manager 64
VMware Horizon View Server 60
VMware Horizon View Composer 60
VMware Horizon View Agent 60
VMware Horizon View Client 64-bit 60
VMware ESXi Hypervisor 55 U2
VMware vCenter Server 55 U2
Microsoft SQL Server 2008R2 Enterprise x64 105016001
Client VM OS Microsoft Windows 7 Enterprise x64 SP1
Management VM OS Microsoft Windows Server 2008 Enterprise R2 x64 SP1
Microsoft Office MS office 2010 Standard Service Pack 1
Login VSI Version 40
Iometer 20060727
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
27 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 9 Average CPU performance per core on one vSphere host during login storm and steady state
Figure 10 Disk space usage during login storm and steady state
0
10
20
30
40
50
60
70
80
90
100
1020 1045 1110 1135 1200 1225
Per
cen
t
Time
CPU Performance
0
50
100
150
200
250
300
1020 1040 1100 1120 1140 1200 1220
GB
Time
Memory Performance
Granted Swap used Shared common
28 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 11 Overall network performance during login storm and steady state
Figure 12 Storage adapter performance during login storm and steady state
0
10000
20000
30000
40000
50000
60000
70000
1020 1045 1110 1135 1200 1225
kBp
s
Time
Network Performance
0
05
1
15
2
25
1020 1045 1110 1135 1200 1225
mSe
c
Time
Storage adaptor performance
29 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
The key observations from the statistics were
CPU utilization was less than the 85 percent threshold throughout the test
Active disk space usage was about 80 percent during the boost storm and about 60 percent
during login storm and steady state There was minimal-or no memory ballooning observed
Network utilization was about 45 percent which included all the networks such as iSCSI SAN VDI
LAN Management LAN and vMotion LAN
Average read- and write latencies at the storage adapter level were very close to the observed
latencies in Fluid Cache 2 msec
632 Monitoring user experience Figure 13 here shows the response time as experienced by each user as calculated by Login VSI The graph
clearly shows that the VSImax (Dynamic) value has not been reached and there were non-responsive or
inactive sessions This means that the array is capable of supporting the 1000 desktops and all users have
acceptable response times for applications that the user is has started
Figure 13 Login VSI user experience monitoring for 800 standard user desktops
30 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
633 Standard user test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SANndashbased VDI solution is able to host 800 virtual desktops and support
a standard user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only operations and
less than 2 percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to handle this login storm easily with low latency mdash it delivered the required 6500 IOPS with less
than 2 milliseconds of write latency with a 99 percent write VDI IO workload
64 Login storm and steady state with high IOPS (LoginVSI Medium +
Iometer) As mentioned earlier Iometer was used in desktop VMs alongside the Login VSI Medium workload to
simulate high IOPS type of VDI environment To mimic actual VDI workload profile the following Iometer
profile was used
20 KB block size 80 percent write 75 percent random with 25 msec burst delay
Figure 14 here shows the various IO characteristics during the login storm and steady state of these tests
Figure 14 IOPS and Cache Hit for the high IOPS test
On the Fluid Cache layer the maximum IOPS reached was approximately 72000 (or 90 IOPSVM) with
cache write-hit 100 percent and read-hit around 95 percent As shown in the Figure 15 the throughput
peaked at greater than 900 MBps with a peak latency of approximately 75 msec
31 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 15 Throughput and Latency for the high IOPS test
32 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
641 Server host performance Similar to the standard user test statistics for the vSphere hosts were captured by using VMware vCenter
Server during the high IOPS (heavy user) test also There are no significant differences in CPU disk space
and network utilization between standard users and heavy users The storage adapter latency is also
showing similar on hosts and observed on Fluid Cache
642 User experience monitoring Figure 16 here shows the response time as experienced by each user as calculated by Login VSI for the
heavy user test The graph shows that the VSImax (Dynamic) value was 796 indicating that the solution is
capable of supporting the 800 user high IOPS desktops with 90 IOPSVM
Figure 16 Login VSI user experience monitoring for 800 user high IOPS desktops
33 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
643 High IOPS (heavy user) test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SAN based VDI solution is able to host 800 virtual desktops and support a
high user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only and less than 2
percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to easily handle this login storm with low latency Subsequently it was able to handle 72000 IOPS
at high IOPS steady state with 90 IOPSVM with a maximum of 75 msec latency
34 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
7 Best practices This section provides the best practices derived from the testing and analysis in Section 6
71 Virtual Desktop Infrastructure This section provides best practices for the implementation of VDI using Dell Fluid Cache for SAN
711 Implement roaming profiles and folder redirection Dell recommends that all users in the VDI environment be configured with roaming profiles and folder
redirection This preserves user profiles and user data across boots while using non-persistent virtual
desktops
Also Dell recommends to use a high performance file service to provide the profile and folder redirection
A separate array may be used to host these volumes for best performance
712 Boot and login storm considerations Section 62 demonstrated the Fluid Cache for SAN performance under boot storm To avoid any potential
IO bursts because of boot storm and degraded user experience and performances Dell recommends that
all or portion of desktops be prebooted Connection brokers such as VMware Horizon View provide the
functionality to configure number of standby desktops
713 Windows 7 master image for desktop VMs Dell recommends that the operating system be customized in order to provide the best performance in a
VDI environment This includes disabling some services which may not be required This can improve
performance for the end user VMware has a specific set of recommendations and settings for Windows 7
and Windows 8 that allow for faster logins quicker screen refreshes and generally better performance
The VMware recommendations for Windows 7 and Windows 8 image optimization can be found here
httpwwwvmwarecomresourcestechresources10157
714 VDI Management infrastructure recommendations Dell recommends to have redundancy and load balancing for all VDI management services in the case of
VMware Horizon View solution as tested here the vSphere Server VMware Horizon View Servers and SQL
Servers Ideally these should be running on clustered hosts with VMware vSphere DRS (distributed
resource scheduler) and HA (high availability) enabled
72 Server host The vSphere servers hosting the infrastructure service providers and the virtual desktops are
recommended to be configured as follows
35 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Follow VMware and Dell best practices for installing and configuring vSphere
Separate virtual switches to segregate iSCSI SAN traffic VDI traffic vMotion traffic and Management
network traffic
Each network path must be assigned to a minimum of two physical NICs for high availability
VMware Knowledge Base article about best practices for installing vSphere 55
httpkbvmwarecomkb2052329
73 Network layer Dell recommends that at least two physical NICs on each vSphere server be dedicated to the VDI network
Use VLANs to segregate different types of network traffic on the same physical network In this case Dell
recommends to separate the infrastructure vMotion and VDI LAN traffic in to separate VLANs
Do not use VLANs to segregate iSCSI SAN and Fluide Cache traffic It is required that SAN and Cache traffic
be on separate dedicated physical network to provide the best performance
Virtual switches in vSphere have a default limit of 120 ports If the number of virtual desktops on each host
exceeds the available ports vSwitch properties should be changed to support the required number of
virtual desktops This change requires a restart of the host vSphere server
On iSCSI SAN switches Spanning tree must be disabled on switch ports connected to end devices for
server and storage ports The PortFast setting must be enabled in the switch configuration for these ports
Jumbo frames and Flow control (if the NICs support it) should be enabled for all components of the iSCSI
network
More information about configuring Dell Networking switches for use with Dell Storage iSCSI SANs is
available here
httpencommunitydellcomtechcenterstoragewwiki4250switch-configuration-guides-by-sisaspx
74 Storage The Dell SC storage arrays combined with Fluid Cache is an excellent platform for providing cost-effective
performance in VDI environments
Fluid Cache for SAN extends the power of Compellent intelligent data placement from the SAN to the
server By providing a single infrastructure for data at both high- and low ends of the performance
spectrum Fluid Cache for SAN with Storage Center 65 array software eliminates the tradeoffs between
server performance and full-featured SAN benefits such as reliability manageability and data protection
Dell recommends to have separate volumes for base image and virtual desktops This enables better
manageability of the volumes easier performance monitoring and allows easy future growth
Dell recommends to use a separate high performance file service to provide file shares for roaming
profiles and user shares
36 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
8 Conclusion The technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed by using a Horizon View VDI platform leveraging Dell Fluid Cache for SAN The storage IO
characteristics under various VDI workload scenarios (boot storm login storm and steady state) along
with performance characteristics throughout the VDI stack (for example vSphere server performance and
user experience) demonstrate the optimal configuration of the infrastructure used for this VDI
deployment For more information about Fluid Cache contact your Dell account manager
37 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
A Horizon view solution configuration
Table 7 Hardware components
Hardware components Description
Virtual Desktops 4 timesDell PowerEdge R720 Servers (Fluid Cache Providers)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
2times350 GB Dell Express Flash PCIe SSDs
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
4 x Dell PowerEdge R720 Servers (Fluid Cache Clients)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55 U2 on all R720 servers Windows 7 (64 Bit) VMs
Infrastructure Servers 2 x Dell PowerEdge R720 servers
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
96 GB RAM
2times300 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55U2 on all R720 servers VMs are loaded with Microsoft Windows 2008 R2
Active Directory
VMware Horizon View 60 Server 1
VMware Horizon View 60 Server 2
VMware vCenter Server 55 update 2
VMware Horizon View Composer
SQL Server
File Server
Login VSI Launchers 8 x Dell PowerEdge M610 servers
2timesIntelreg Xeonreg E-5503 200 GHz Processors
16 GB RAM
4times146 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57711 10GbE NIC
ESXi 51 installed on all R810 servers VMs are loaded with Microsoft Windows 7 64bit Each VM supports up to 30 Login VSI launcher sessions
38 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Network Management VDI LAN
1timesDell Force10 S55 1Gb Ethernet Switch
iSCSI SAN
1timesDell Force10 S4810 10Gb Ethernet Switch
Cache network
1timesDell Force10 S4810 10Gb Ethernet Switch
One Force10 S4810 switch might suffice for all the cache iSCSI SAN VDI LAN and management traffic
Storage 2timesDell Compellent SC8000 controllers 4times6Gb SAS 4-port PCI-E Full-height cards for back-end connectivity 2times10Gb iSCSI 2 port PCI-E Low-profile IO cards for front end connectivity 1timesDell Compellent SC200 disk enclosures 12times4TB NL-SAS 6Gb 72K 35rdquo drives
User Data Infrastructure VMs Virtual Desktops
Performance Monitoring
Dell Compellent Enterprise Manager Dell Fluid Cache for SAN performance monitoring tool () vCenter Performance monitoring Liquidware Stratusphere UX
Performance monitoring on Compellent arrays Fluid Cache performance monitoring Performance monitoring and capture at the ESXi host User experience monitoring on the virtual desktop
39 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 8 Software components
Software components Description Version
Dell Fluid Cache for SAN 20
Dell Compellent Storage Center 64
Dell Compellent Enterprise Manager 64
VMware Horizon View Server 60
VMware Horizon View Composer 60
VMware Horizon View Agent 60
VMware Horizon View Client 64-bit 60
VMware ESXi Hypervisor 55 U2
VMware vCenter Server 55 U2
Microsoft SQL Server 2008R2 Enterprise x64 105016001
Client VM OS Microsoft Windows 7 Enterprise x64 SP1
Management VM OS Microsoft Windows Server 2008 Enterprise R2 x64 SP1
Microsoft Office MS office 2010 Standard Service Pack 1
Login VSI Version 40
Iometer 20060727
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
28 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 11 Overall network performance during login storm and steady state
Figure 12 Storage adapter performance during login storm and steady state
0
10000
20000
30000
40000
50000
60000
70000
1020 1045 1110 1135 1200 1225
kBp
s
Time
Network Performance
0
05
1
15
2
25
1020 1045 1110 1135 1200 1225
mSe
c
Time
Storage adaptor performance
29 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
The key observations from the statistics were
CPU utilization was less than the 85 percent threshold throughout the test
Active disk space usage was about 80 percent during the boost storm and about 60 percent
during login storm and steady state There was minimal-or no memory ballooning observed
Network utilization was about 45 percent which included all the networks such as iSCSI SAN VDI
LAN Management LAN and vMotion LAN
Average read- and write latencies at the storage adapter level were very close to the observed
latencies in Fluid Cache 2 msec
632 Monitoring user experience Figure 13 here shows the response time as experienced by each user as calculated by Login VSI The graph
clearly shows that the VSImax (Dynamic) value has not been reached and there were non-responsive or
inactive sessions This means that the array is capable of supporting the 1000 desktops and all users have
acceptable response times for applications that the user is has started
Figure 13 Login VSI user experience monitoring for 800 standard user desktops
30 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
633 Standard user test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SANndashbased VDI solution is able to host 800 virtual desktops and support
a standard user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only operations and
less than 2 percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to handle this login storm easily with low latency mdash it delivered the required 6500 IOPS with less
than 2 milliseconds of write latency with a 99 percent write VDI IO workload
64 Login storm and steady state with high IOPS (LoginVSI Medium +
Iometer) As mentioned earlier Iometer was used in desktop VMs alongside the Login VSI Medium workload to
simulate high IOPS type of VDI environment To mimic actual VDI workload profile the following Iometer
profile was used
20 KB block size 80 percent write 75 percent random with 25 msec burst delay
Figure 14 here shows the various IO characteristics during the login storm and steady state of these tests
Figure 14 IOPS and Cache Hit for the high IOPS test
On the Fluid Cache layer the maximum IOPS reached was approximately 72000 (or 90 IOPSVM) with
cache write-hit 100 percent and read-hit around 95 percent As shown in the Figure 15 the throughput
peaked at greater than 900 MBps with a peak latency of approximately 75 msec
31 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 15 Throughput and Latency for the high IOPS test
32 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
641 Server host performance Similar to the standard user test statistics for the vSphere hosts were captured by using VMware vCenter
Server during the high IOPS (heavy user) test also There are no significant differences in CPU disk space
and network utilization between standard users and heavy users The storage adapter latency is also
showing similar on hosts and observed on Fluid Cache
642 User experience monitoring Figure 16 here shows the response time as experienced by each user as calculated by Login VSI for the
heavy user test The graph shows that the VSImax (Dynamic) value was 796 indicating that the solution is
capable of supporting the 800 user high IOPS desktops with 90 IOPSVM
Figure 16 Login VSI user experience monitoring for 800 user high IOPS desktops
33 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
643 High IOPS (heavy user) test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SAN based VDI solution is able to host 800 virtual desktops and support a
high user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only and less than 2
percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to easily handle this login storm with low latency Subsequently it was able to handle 72000 IOPS
at high IOPS steady state with 90 IOPSVM with a maximum of 75 msec latency
34 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
7 Best practices This section provides the best practices derived from the testing and analysis in Section 6
71 Virtual Desktop Infrastructure This section provides best practices for the implementation of VDI using Dell Fluid Cache for SAN
711 Implement roaming profiles and folder redirection Dell recommends that all users in the VDI environment be configured with roaming profiles and folder
redirection This preserves user profiles and user data across boots while using non-persistent virtual
desktops
Also Dell recommends to use a high performance file service to provide the profile and folder redirection
A separate array may be used to host these volumes for best performance
712 Boot and login storm considerations Section 62 demonstrated the Fluid Cache for SAN performance under boot storm To avoid any potential
IO bursts because of boot storm and degraded user experience and performances Dell recommends that
all or portion of desktops be prebooted Connection brokers such as VMware Horizon View provide the
functionality to configure number of standby desktops
713 Windows 7 master image for desktop VMs Dell recommends that the operating system be customized in order to provide the best performance in a
VDI environment This includes disabling some services which may not be required This can improve
performance for the end user VMware has a specific set of recommendations and settings for Windows 7
and Windows 8 that allow for faster logins quicker screen refreshes and generally better performance
The VMware recommendations for Windows 7 and Windows 8 image optimization can be found here
httpwwwvmwarecomresourcestechresources10157
714 VDI Management infrastructure recommendations Dell recommends to have redundancy and load balancing for all VDI management services in the case of
VMware Horizon View solution as tested here the vSphere Server VMware Horizon View Servers and SQL
Servers Ideally these should be running on clustered hosts with VMware vSphere DRS (distributed
resource scheduler) and HA (high availability) enabled
72 Server host The vSphere servers hosting the infrastructure service providers and the virtual desktops are
recommended to be configured as follows
35 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Follow VMware and Dell best practices for installing and configuring vSphere
Separate virtual switches to segregate iSCSI SAN traffic VDI traffic vMotion traffic and Management
network traffic
Each network path must be assigned to a minimum of two physical NICs for high availability
VMware Knowledge Base article about best practices for installing vSphere 55
httpkbvmwarecomkb2052329
73 Network layer Dell recommends that at least two physical NICs on each vSphere server be dedicated to the VDI network
Use VLANs to segregate different types of network traffic on the same physical network In this case Dell
recommends to separate the infrastructure vMotion and VDI LAN traffic in to separate VLANs
Do not use VLANs to segregate iSCSI SAN and Fluide Cache traffic It is required that SAN and Cache traffic
be on separate dedicated physical network to provide the best performance
Virtual switches in vSphere have a default limit of 120 ports If the number of virtual desktops on each host
exceeds the available ports vSwitch properties should be changed to support the required number of
virtual desktops This change requires a restart of the host vSphere server
On iSCSI SAN switches Spanning tree must be disabled on switch ports connected to end devices for
server and storage ports The PortFast setting must be enabled in the switch configuration for these ports
Jumbo frames and Flow control (if the NICs support it) should be enabled for all components of the iSCSI
network
More information about configuring Dell Networking switches for use with Dell Storage iSCSI SANs is
available here
httpencommunitydellcomtechcenterstoragewwiki4250switch-configuration-guides-by-sisaspx
74 Storage The Dell SC storage arrays combined with Fluid Cache is an excellent platform for providing cost-effective
performance in VDI environments
Fluid Cache for SAN extends the power of Compellent intelligent data placement from the SAN to the
server By providing a single infrastructure for data at both high- and low ends of the performance
spectrum Fluid Cache for SAN with Storage Center 65 array software eliminates the tradeoffs between
server performance and full-featured SAN benefits such as reliability manageability and data protection
Dell recommends to have separate volumes for base image and virtual desktops This enables better
manageability of the volumes easier performance monitoring and allows easy future growth
Dell recommends to use a separate high performance file service to provide file shares for roaming
profiles and user shares
36 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
8 Conclusion The technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed by using a Horizon View VDI platform leveraging Dell Fluid Cache for SAN The storage IO
characteristics under various VDI workload scenarios (boot storm login storm and steady state) along
with performance characteristics throughout the VDI stack (for example vSphere server performance and
user experience) demonstrate the optimal configuration of the infrastructure used for this VDI
deployment For more information about Fluid Cache contact your Dell account manager
37 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
A Horizon view solution configuration
Table 7 Hardware components
Hardware components Description
Virtual Desktops 4 timesDell PowerEdge R720 Servers (Fluid Cache Providers)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
2times350 GB Dell Express Flash PCIe SSDs
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
4 x Dell PowerEdge R720 Servers (Fluid Cache Clients)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55 U2 on all R720 servers Windows 7 (64 Bit) VMs
Infrastructure Servers 2 x Dell PowerEdge R720 servers
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
96 GB RAM
2times300 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55U2 on all R720 servers VMs are loaded with Microsoft Windows 2008 R2
Active Directory
VMware Horizon View 60 Server 1
VMware Horizon View 60 Server 2
VMware vCenter Server 55 update 2
VMware Horizon View Composer
SQL Server
File Server
Login VSI Launchers 8 x Dell PowerEdge M610 servers
2timesIntelreg Xeonreg E-5503 200 GHz Processors
16 GB RAM
4times146 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57711 10GbE NIC
ESXi 51 installed on all R810 servers VMs are loaded with Microsoft Windows 7 64bit Each VM supports up to 30 Login VSI launcher sessions
38 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Network Management VDI LAN
1timesDell Force10 S55 1Gb Ethernet Switch
iSCSI SAN
1timesDell Force10 S4810 10Gb Ethernet Switch
Cache network
1timesDell Force10 S4810 10Gb Ethernet Switch
One Force10 S4810 switch might suffice for all the cache iSCSI SAN VDI LAN and management traffic
Storage 2timesDell Compellent SC8000 controllers 4times6Gb SAS 4-port PCI-E Full-height cards for back-end connectivity 2times10Gb iSCSI 2 port PCI-E Low-profile IO cards for front end connectivity 1timesDell Compellent SC200 disk enclosures 12times4TB NL-SAS 6Gb 72K 35rdquo drives
User Data Infrastructure VMs Virtual Desktops
Performance Monitoring
Dell Compellent Enterprise Manager Dell Fluid Cache for SAN performance monitoring tool () vCenter Performance monitoring Liquidware Stratusphere UX
Performance monitoring on Compellent arrays Fluid Cache performance monitoring Performance monitoring and capture at the ESXi host User experience monitoring on the virtual desktop
39 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 8 Software components
Software components Description Version
Dell Fluid Cache for SAN 20
Dell Compellent Storage Center 64
Dell Compellent Enterprise Manager 64
VMware Horizon View Server 60
VMware Horizon View Composer 60
VMware Horizon View Agent 60
VMware Horizon View Client 64-bit 60
VMware ESXi Hypervisor 55 U2
VMware vCenter Server 55 U2
Microsoft SQL Server 2008R2 Enterprise x64 105016001
Client VM OS Microsoft Windows 7 Enterprise x64 SP1
Management VM OS Microsoft Windows Server 2008 Enterprise R2 x64 SP1
Microsoft Office MS office 2010 Standard Service Pack 1
Login VSI Version 40
Iometer 20060727
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
29 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
The key observations from the statistics were
CPU utilization was less than the 85 percent threshold throughout the test
Active disk space usage was about 80 percent during the boost storm and about 60 percent
during login storm and steady state There was minimal-or no memory ballooning observed
Network utilization was about 45 percent which included all the networks such as iSCSI SAN VDI
LAN Management LAN and vMotion LAN
Average read- and write latencies at the storage adapter level were very close to the observed
latencies in Fluid Cache 2 msec
632 Monitoring user experience Figure 13 here shows the response time as experienced by each user as calculated by Login VSI The graph
clearly shows that the VSImax (Dynamic) value has not been reached and there were non-responsive or
inactive sessions This means that the array is capable of supporting the 1000 desktops and all users have
acceptable response times for applications that the user is has started
Figure 13 Login VSI user experience monitoring for 800 standard user desktops
30 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
633 Standard user test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SANndashbased VDI solution is able to host 800 virtual desktops and support
a standard user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only operations and
less than 2 percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to handle this login storm easily with low latency mdash it delivered the required 6500 IOPS with less
than 2 milliseconds of write latency with a 99 percent write VDI IO workload
64 Login storm and steady state with high IOPS (LoginVSI Medium +
Iometer) As mentioned earlier Iometer was used in desktop VMs alongside the Login VSI Medium workload to
simulate high IOPS type of VDI environment To mimic actual VDI workload profile the following Iometer
profile was used
20 KB block size 80 percent write 75 percent random with 25 msec burst delay
Figure 14 here shows the various IO characteristics during the login storm and steady state of these tests
Figure 14 IOPS and Cache Hit for the high IOPS test
On the Fluid Cache layer the maximum IOPS reached was approximately 72000 (or 90 IOPSVM) with
cache write-hit 100 percent and read-hit around 95 percent As shown in the Figure 15 the throughput
peaked at greater than 900 MBps with a peak latency of approximately 75 msec
31 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 15 Throughput and Latency for the high IOPS test
32 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
641 Server host performance Similar to the standard user test statistics for the vSphere hosts were captured by using VMware vCenter
Server during the high IOPS (heavy user) test also There are no significant differences in CPU disk space
and network utilization between standard users and heavy users The storage adapter latency is also
showing similar on hosts and observed on Fluid Cache
642 User experience monitoring Figure 16 here shows the response time as experienced by each user as calculated by Login VSI for the
heavy user test The graph shows that the VSImax (Dynamic) value was 796 indicating that the solution is
capable of supporting the 800 user high IOPS desktops with 90 IOPSVM
Figure 16 Login VSI user experience monitoring for 800 user high IOPS desktops
33 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
643 High IOPS (heavy user) test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SAN based VDI solution is able to host 800 virtual desktops and support a
high user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only and less than 2
percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to easily handle this login storm with low latency Subsequently it was able to handle 72000 IOPS
at high IOPS steady state with 90 IOPSVM with a maximum of 75 msec latency
34 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
7 Best practices This section provides the best practices derived from the testing and analysis in Section 6
71 Virtual Desktop Infrastructure This section provides best practices for the implementation of VDI using Dell Fluid Cache for SAN
711 Implement roaming profiles and folder redirection Dell recommends that all users in the VDI environment be configured with roaming profiles and folder
redirection This preserves user profiles and user data across boots while using non-persistent virtual
desktops
Also Dell recommends to use a high performance file service to provide the profile and folder redirection
A separate array may be used to host these volumes for best performance
712 Boot and login storm considerations Section 62 demonstrated the Fluid Cache for SAN performance under boot storm To avoid any potential
IO bursts because of boot storm and degraded user experience and performances Dell recommends that
all or portion of desktops be prebooted Connection brokers such as VMware Horizon View provide the
functionality to configure number of standby desktops
713 Windows 7 master image for desktop VMs Dell recommends that the operating system be customized in order to provide the best performance in a
VDI environment This includes disabling some services which may not be required This can improve
performance for the end user VMware has a specific set of recommendations and settings for Windows 7
and Windows 8 that allow for faster logins quicker screen refreshes and generally better performance
The VMware recommendations for Windows 7 and Windows 8 image optimization can be found here
httpwwwvmwarecomresourcestechresources10157
714 VDI Management infrastructure recommendations Dell recommends to have redundancy and load balancing for all VDI management services in the case of
VMware Horizon View solution as tested here the vSphere Server VMware Horizon View Servers and SQL
Servers Ideally these should be running on clustered hosts with VMware vSphere DRS (distributed
resource scheduler) and HA (high availability) enabled
72 Server host The vSphere servers hosting the infrastructure service providers and the virtual desktops are
recommended to be configured as follows
35 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Follow VMware and Dell best practices for installing and configuring vSphere
Separate virtual switches to segregate iSCSI SAN traffic VDI traffic vMotion traffic and Management
network traffic
Each network path must be assigned to a minimum of two physical NICs for high availability
VMware Knowledge Base article about best practices for installing vSphere 55
httpkbvmwarecomkb2052329
73 Network layer Dell recommends that at least two physical NICs on each vSphere server be dedicated to the VDI network
Use VLANs to segregate different types of network traffic on the same physical network In this case Dell
recommends to separate the infrastructure vMotion and VDI LAN traffic in to separate VLANs
Do not use VLANs to segregate iSCSI SAN and Fluide Cache traffic It is required that SAN and Cache traffic
be on separate dedicated physical network to provide the best performance
Virtual switches in vSphere have a default limit of 120 ports If the number of virtual desktops on each host
exceeds the available ports vSwitch properties should be changed to support the required number of
virtual desktops This change requires a restart of the host vSphere server
On iSCSI SAN switches Spanning tree must be disabled on switch ports connected to end devices for
server and storage ports The PortFast setting must be enabled in the switch configuration for these ports
Jumbo frames and Flow control (if the NICs support it) should be enabled for all components of the iSCSI
network
More information about configuring Dell Networking switches for use with Dell Storage iSCSI SANs is
available here
httpencommunitydellcomtechcenterstoragewwiki4250switch-configuration-guides-by-sisaspx
74 Storage The Dell SC storage arrays combined with Fluid Cache is an excellent platform for providing cost-effective
performance in VDI environments
Fluid Cache for SAN extends the power of Compellent intelligent data placement from the SAN to the
server By providing a single infrastructure for data at both high- and low ends of the performance
spectrum Fluid Cache for SAN with Storage Center 65 array software eliminates the tradeoffs between
server performance and full-featured SAN benefits such as reliability manageability and data protection
Dell recommends to have separate volumes for base image and virtual desktops This enables better
manageability of the volumes easier performance monitoring and allows easy future growth
Dell recommends to use a separate high performance file service to provide file shares for roaming
profiles and user shares
36 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
8 Conclusion The technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed by using a Horizon View VDI platform leveraging Dell Fluid Cache for SAN The storage IO
characteristics under various VDI workload scenarios (boot storm login storm and steady state) along
with performance characteristics throughout the VDI stack (for example vSphere server performance and
user experience) demonstrate the optimal configuration of the infrastructure used for this VDI
deployment For more information about Fluid Cache contact your Dell account manager
37 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
A Horizon view solution configuration
Table 7 Hardware components
Hardware components Description
Virtual Desktops 4 timesDell PowerEdge R720 Servers (Fluid Cache Providers)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
2times350 GB Dell Express Flash PCIe SSDs
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
4 x Dell PowerEdge R720 Servers (Fluid Cache Clients)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55 U2 on all R720 servers Windows 7 (64 Bit) VMs
Infrastructure Servers 2 x Dell PowerEdge R720 servers
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
96 GB RAM
2times300 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55U2 on all R720 servers VMs are loaded with Microsoft Windows 2008 R2
Active Directory
VMware Horizon View 60 Server 1
VMware Horizon View 60 Server 2
VMware vCenter Server 55 update 2
VMware Horizon View Composer
SQL Server
File Server
Login VSI Launchers 8 x Dell PowerEdge M610 servers
2timesIntelreg Xeonreg E-5503 200 GHz Processors
16 GB RAM
4times146 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57711 10GbE NIC
ESXi 51 installed on all R810 servers VMs are loaded with Microsoft Windows 7 64bit Each VM supports up to 30 Login VSI launcher sessions
38 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Network Management VDI LAN
1timesDell Force10 S55 1Gb Ethernet Switch
iSCSI SAN
1timesDell Force10 S4810 10Gb Ethernet Switch
Cache network
1timesDell Force10 S4810 10Gb Ethernet Switch
One Force10 S4810 switch might suffice for all the cache iSCSI SAN VDI LAN and management traffic
Storage 2timesDell Compellent SC8000 controllers 4times6Gb SAS 4-port PCI-E Full-height cards for back-end connectivity 2times10Gb iSCSI 2 port PCI-E Low-profile IO cards for front end connectivity 1timesDell Compellent SC200 disk enclosures 12times4TB NL-SAS 6Gb 72K 35rdquo drives
User Data Infrastructure VMs Virtual Desktops
Performance Monitoring
Dell Compellent Enterprise Manager Dell Fluid Cache for SAN performance monitoring tool () vCenter Performance monitoring Liquidware Stratusphere UX
Performance monitoring on Compellent arrays Fluid Cache performance monitoring Performance monitoring and capture at the ESXi host User experience monitoring on the virtual desktop
39 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 8 Software components
Software components Description Version
Dell Fluid Cache for SAN 20
Dell Compellent Storage Center 64
Dell Compellent Enterprise Manager 64
VMware Horizon View Server 60
VMware Horizon View Composer 60
VMware Horizon View Agent 60
VMware Horizon View Client 64-bit 60
VMware ESXi Hypervisor 55 U2
VMware vCenter Server 55 U2
Microsoft SQL Server 2008R2 Enterprise x64 105016001
Client VM OS Microsoft Windows 7 Enterprise x64 SP1
Management VM OS Microsoft Windows Server 2008 Enterprise R2 x64 SP1
Microsoft Office MS office 2010 Standard Service Pack 1
Login VSI Version 40
Iometer 20060727
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
30 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
633 Standard user test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SANndashbased VDI solution is able to host 800 virtual desktops and support
a standard user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only operations and
less than 2 percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to handle this login storm easily with low latency mdash it delivered the required 6500 IOPS with less
than 2 milliseconds of write latency with a 99 percent write VDI IO workload
64 Login storm and steady state with high IOPS (LoginVSI Medium +
Iometer) As mentioned earlier Iometer was used in desktop VMs alongside the Login VSI Medium workload to
simulate high IOPS type of VDI environment To mimic actual VDI workload profile the following Iometer
profile was used
20 KB block size 80 percent write 75 percent random with 25 msec burst delay
Figure 14 here shows the various IO characteristics during the login storm and steady state of these tests
Figure 14 IOPS and Cache Hit for the high IOPS test
On the Fluid Cache layer the maximum IOPS reached was approximately 72000 (or 90 IOPSVM) with
cache write-hit 100 percent and read-hit around 95 percent As shown in the Figure 15 the throughput
peaked at greater than 900 MBps with a peak latency of approximately 75 msec
31 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 15 Throughput and Latency for the high IOPS test
32 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
641 Server host performance Similar to the standard user test statistics for the vSphere hosts were captured by using VMware vCenter
Server during the high IOPS (heavy user) test also There are no significant differences in CPU disk space
and network utilization between standard users and heavy users The storage adapter latency is also
showing similar on hosts and observed on Fluid Cache
642 User experience monitoring Figure 16 here shows the response time as experienced by each user as calculated by Login VSI for the
heavy user test The graph shows that the VSImax (Dynamic) value was 796 indicating that the solution is
capable of supporting the 800 user high IOPS desktops with 90 IOPSVM
Figure 16 Login VSI user experience monitoring for 800 user high IOPS desktops
33 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
643 High IOPS (heavy user) test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SAN based VDI solution is able to host 800 virtual desktops and support a
high user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only and less than 2
percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to easily handle this login storm with low latency Subsequently it was able to handle 72000 IOPS
at high IOPS steady state with 90 IOPSVM with a maximum of 75 msec latency
34 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
7 Best practices This section provides the best practices derived from the testing and analysis in Section 6
71 Virtual Desktop Infrastructure This section provides best practices for the implementation of VDI using Dell Fluid Cache for SAN
711 Implement roaming profiles and folder redirection Dell recommends that all users in the VDI environment be configured with roaming profiles and folder
redirection This preserves user profiles and user data across boots while using non-persistent virtual
desktops
Also Dell recommends to use a high performance file service to provide the profile and folder redirection
A separate array may be used to host these volumes for best performance
712 Boot and login storm considerations Section 62 demonstrated the Fluid Cache for SAN performance under boot storm To avoid any potential
IO bursts because of boot storm and degraded user experience and performances Dell recommends that
all or portion of desktops be prebooted Connection brokers such as VMware Horizon View provide the
functionality to configure number of standby desktops
713 Windows 7 master image for desktop VMs Dell recommends that the operating system be customized in order to provide the best performance in a
VDI environment This includes disabling some services which may not be required This can improve
performance for the end user VMware has a specific set of recommendations and settings for Windows 7
and Windows 8 that allow for faster logins quicker screen refreshes and generally better performance
The VMware recommendations for Windows 7 and Windows 8 image optimization can be found here
httpwwwvmwarecomresourcestechresources10157
714 VDI Management infrastructure recommendations Dell recommends to have redundancy and load balancing for all VDI management services in the case of
VMware Horizon View solution as tested here the vSphere Server VMware Horizon View Servers and SQL
Servers Ideally these should be running on clustered hosts with VMware vSphere DRS (distributed
resource scheduler) and HA (high availability) enabled
72 Server host The vSphere servers hosting the infrastructure service providers and the virtual desktops are
recommended to be configured as follows
35 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Follow VMware and Dell best practices for installing and configuring vSphere
Separate virtual switches to segregate iSCSI SAN traffic VDI traffic vMotion traffic and Management
network traffic
Each network path must be assigned to a minimum of two physical NICs for high availability
VMware Knowledge Base article about best practices for installing vSphere 55
httpkbvmwarecomkb2052329
73 Network layer Dell recommends that at least two physical NICs on each vSphere server be dedicated to the VDI network
Use VLANs to segregate different types of network traffic on the same physical network In this case Dell
recommends to separate the infrastructure vMotion and VDI LAN traffic in to separate VLANs
Do not use VLANs to segregate iSCSI SAN and Fluide Cache traffic It is required that SAN and Cache traffic
be on separate dedicated physical network to provide the best performance
Virtual switches in vSphere have a default limit of 120 ports If the number of virtual desktops on each host
exceeds the available ports vSwitch properties should be changed to support the required number of
virtual desktops This change requires a restart of the host vSphere server
On iSCSI SAN switches Spanning tree must be disabled on switch ports connected to end devices for
server and storage ports The PortFast setting must be enabled in the switch configuration for these ports
Jumbo frames and Flow control (if the NICs support it) should be enabled for all components of the iSCSI
network
More information about configuring Dell Networking switches for use with Dell Storage iSCSI SANs is
available here
httpencommunitydellcomtechcenterstoragewwiki4250switch-configuration-guides-by-sisaspx
74 Storage The Dell SC storage arrays combined with Fluid Cache is an excellent platform for providing cost-effective
performance in VDI environments
Fluid Cache for SAN extends the power of Compellent intelligent data placement from the SAN to the
server By providing a single infrastructure for data at both high- and low ends of the performance
spectrum Fluid Cache for SAN with Storage Center 65 array software eliminates the tradeoffs between
server performance and full-featured SAN benefits such as reliability manageability and data protection
Dell recommends to have separate volumes for base image and virtual desktops This enables better
manageability of the volumes easier performance monitoring and allows easy future growth
Dell recommends to use a separate high performance file service to provide file shares for roaming
profiles and user shares
36 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
8 Conclusion The technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed by using a Horizon View VDI platform leveraging Dell Fluid Cache for SAN The storage IO
characteristics under various VDI workload scenarios (boot storm login storm and steady state) along
with performance characteristics throughout the VDI stack (for example vSphere server performance and
user experience) demonstrate the optimal configuration of the infrastructure used for this VDI
deployment For more information about Fluid Cache contact your Dell account manager
37 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
A Horizon view solution configuration
Table 7 Hardware components
Hardware components Description
Virtual Desktops 4 timesDell PowerEdge R720 Servers (Fluid Cache Providers)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
2times350 GB Dell Express Flash PCIe SSDs
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
4 x Dell PowerEdge R720 Servers (Fluid Cache Clients)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55 U2 on all R720 servers Windows 7 (64 Bit) VMs
Infrastructure Servers 2 x Dell PowerEdge R720 servers
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
96 GB RAM
2times300 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55U2 on all R720 servers VMs are loaded with Microsoft Windows 2008 R2
Active Directory
VMware Horizon View 60 Server 1
VMware Horizon View 60 Server 2
VMware vCenter Server 55 update 2
VMware Horizon View Composer
SQL Server
File Server
Login VSI Launchers 8 x Dell PowerEdge M610 servers
2timesIntelreg Xeonreg E-5503 200 GHz Processors
16 GB RAM
4times146 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57711 10GbE NIC
ESXi 51 installed on all R810 servers VMs are loaded with Microsoft Windows 7 64bit Each VM supports up to 30 Login VSI launcher sessions
38 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Network Management VDI LAN
1timesDell Force10 S55 1Gb Ethernet Switch
iSCSI SAN
1timesDell Force10 S4810 10Gb Ethernet Switch
Cache network
1timesDell Force10 S4810 10Gb Ethernet Switch
One Force10 S4810 switch might suffice for all the cache iSCSI SAN VDI LAN and management traffic
Storage 2timesDell Compellent SC8000 controllers 4times6Gb SAS 4-port PCI-E Full-height cards for back-end connectivity 2times10Gb iSCSI 2 port PCI-E Low-profile IO cards for front end connectivity 1timesDell Compellent SC200 disk enclosures 12times4TB NL-SAS 6Gb 72K 35rdquo drives
User Data Infrastructure VMs Virtual Desktops
Performance Monitoring
Dell Compellent Enterprise Manager Dell Fluid Cache for SAN performance monitoring tool () vCenter Performance monitoring Liquidware Stratusphere UX
Performance monitoring on Compellent arrays Fluid Cache performance monitoring Performance monitoring and capture at the ESXi host User experience monitoring on the virtual desktop
39 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 8 Software components
Software components Description Version
Dell Fluid Cache for SAN 20
Dell Compellent Storage Center 64
Dell Compellent Enterprise Manager 64
VMware Horizon View Server 60
VMware Horizon View Composer 60
VMware Horizon View Agent 60
VMware Horizon View Client 64-bit 60
VMware ESXi Hypervisor 55 U2
VMware vCenter Server 55 U2
Microsoft SQL Server 2008R2 Enterprise x64 105016001
Client VM OS Microsoft Windows 7 Enterprise x64 SP1
Management VM OS Microsoft Windows Server 2008 Enterprise R2 x64 SP1
Microsoft Office MS office 2010 Standard Service Pack 1
Login VSI Version 40
Iometer 20060727
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
31 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Figure 15 Throughput and Latency for the high IOPS test
32 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
641 Server host performance Similar to the standard user test statistics for the vSphere hosts were captured by using VMware vCenter
Server during the high IOPS (heavy user) test also There are no significant differences in CPU disk space
and network utilization between standard users and heavy users The storage adapter latency is also
showing similar on hosts and observed on Fluid Cache
642 User experience monitoring Figure 16 here shows the response time as experienced by each user as calculated by Login VSI for the
heavy user test The graph shows that the VSImax (Dynamic) value was 796 indicating that the solution is
capable of supporting the 800 user high IOPS desktops with 90 IOPSVM
Figure 16 Login VSI user experience monitoring for 800 user high IOPS desktops
33 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
643 High IOPS (heavy user) test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SAN based VDI solution is able to host 800 virtual desktops and support a
high user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only and less than 2
percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to easily handle this login storm with low latency Subsequently it was able to handle 72000 IOPS
at high IOPS steady state with 90 IOPSVM with a maximum of 75 msec latency
34 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
7 Best practices This section provides the best practices derived from the testing and analysis in Section 6
71 Virtual Desktop Infrastructure This section provides best practices for the implementation of VDI using Dell Fluid Cache for SAN
711 Implement roaming profiles and folder redirection Dell recommends that all users in the VDI environment be configured with roaming profiles and folder
redirection This preserves user profiles and user data across boots while using non-persistent virtual
desktops
Also Dell recommends to use a high performance file service to provide the profile and folder redirection
A separate array may be used to host these volumes for best performance
712 Boot and login storm considerations Section 62 demonstrated the Fluid Cache for SAN performance under boot storm To avoid any potential
IO bursts because of boot storm and degraded user experience and performances Dell recommends that
all or portion of desktops be prebooted Connection brokers such as VMware Horizon View provide the
functionality to configure number of standby desktops
713 Windows 7 master image for desktop VMs Dell recommends that the operating system be customized in order to provide the best performance in a
VDI environment This includes disabling some services which may not be required This can improve
performance for the end user VMware has a specific set of recommendations and settings for Windows 7
and Windows 8 that allow for faster logins quicker screen refreshes and generally better performance
The VMware recommendations for Windows 7 and Windows 8 image optimization can be found here
httpwwwvmwarecomresourcestechresources10157
714 VDI Management infrastructure recommendations Dell recommends to have redundancy and load balancing for all VDI management services in the case of
VMware Horizon View solution as tested here the vSphere Server VMware Horizon View Servers and SQL
Servers Ideally these should be running on clustered hosts with VMware vSphere DRS (distributed
resource scheduler) and HA (high availability) enabled
72 Server host The vSphere servers hosting the infrastructure service providers and the virtual desktops are
recommended to be configured as follows
35 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Follow VMware and Dell best practices for installing and configuring vSphere
Separate virtual switches to segregate iSCSI SAN traffic VDI traffic vMotion traffic and Management
network traffic
Each network path must be assigned to a minimum of two physical NICs for high availability
VMware Knowledge Base article about best practices for installing vSphere 55
httpkbvmwarecomkb2052329
73 Network layer Dell recommends that at least two physical NICs on each vSphere server be dedicated to the VDI network
Use VLANs to segregate different types of network traffic on the same physical network In this case Dell
recommends to separate the infrastructure vMotion and VDI LAN traffic in to separate VLANs
Do not use VLANs to segregate iSCSI SAN and Fluide Cache traffic It is required that SAN and Cache traffic
be on separate dedicated physical network to provide the best performance
Virtual switches in vSphere have a default limit of 120 ports If the number of virtual desktops on each host
exceeds the available ports vSwitch properties should be changed to support the required number of
virtual desktops This change requires a restart of the host vSphere server
On iSCSI SAN switches Spanning tree must be disabled on switch ports connected to end devices for
server and storage ports The PortFast setting must be enabled in the switch configuration for these ports
Jumbo frames and Flow control (if the NICs support it) should be enabled for all components of the iSCSI
network
More information about configuring Dell Networking switches for use with Dell Storage iSCSI SANs is
available here
httpencommunitydellcomtechcenterstoragewwiki4250switch-configuration-guides-by-sisaspx
74 Storage The Dell SC storage arrays combined with Fluid Cache is an excellent platform for providing cost-effective
performance in VDI environments
Fluid Cache for SAN extends the power of Compellent intelligent data placement from the SAN to the
server By providing a single infrastructure for data at both high- and low ends of the performance
spectrum Fluid Cache for SAN with Storage Center 65 array software eliminates the tradeoffs between
server performance and full-featured SAN benefits such as reliability manageability and data protection
Dell recommends to have separate volumes for base image and virtual desktops This enables better
manageability of the volumes easier performance monitoring and allows easy future growth
Dell recommends to use a separate high performance file service to provide file shares for roaming
profiles and user shares
36 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
8 Conclusion The technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed by using a Horizon View VDI platform leveraging Dell Fluid Cache for SAN The storage IO
characteristics under various VDI workload scenarios (boot storm login storm and steady state) along
with performance characteristics throughout the VDI stack (for example vSphere server performance and
user experience) demonstrate the optimal configuration of the infrastructure used for this VDI
deployment For more information about Fluid Cache contact your Dell account manager
37 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
A Horizon view solution configuration
Table 7 Hardware components
Hardware components Description
Virtual Desktops 4 timesDell PowerEdge R720 Servers (Fluid Cache Providers)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
2times350 GB Dell Express Flash PCIe SSDs
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
4 x Dell PowerEdge R720 Servers (Fluid Cache Clients)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55 U2 on all R720 servers Windows 7 (64 Bit) VMs
Infrastructure Servers 2 x Dell PowerEdge R720 servers
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
96 GB RAM
2times300 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55U2 on all R720 servers VMs are loaded with Microsoft Windows 2008 R2
Active Directory
VMware Horizon View 60 Server 1
VMware Horizon View 60 Server 2
VMware vCenter Server 55 update 2
VMware Horizon View Composer
SQL Server
File Server
Login VSI Launchers 8 x Dell PowerEdge M610 servers
2timesIntelreg Xeonreg E-5503 200 GHz Processors
16 GB RAM
4times146 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57711 10GbE NIC
ESXi 51 installed on all R810 servers VMs are loaded with Microsoft Windows 7 64bit Each VM supports up to 30 Login VSI launcher sessions
38 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Network Management VDI LAN
1timesDell Force10 S55 1Gb Ethernet Switch
iSCSI SAN
1timesDell Force10 S4810 10Gb Ethernet Switch
Cache network
1timesDell Force10 S4810 10Gb Ethernet Switch
One Force10 S4810 switch might suffice for all the cache iSCSI SAN VDI LAN and management traffic
Storage 2timesDell Compellent SC8000 controllers 4times6Gb SAS 4-port PCI-E Full-height cards for back-end connectivity 2times10Gb iSCSI 2 port PCI-E Low-profile IO cards for front end connectivity 1timesDell Compellent SC200 disk enclosures 12times4TB NL-SAS 6Gb 72K 35rdquo drives
User Data Infrastructure VMs Virtual Desktops
Performance Monitoring
Dell Compellent Enterprise Manager Dell Fluid Cache for SAN performance monitoring tool () vCenter Performance monitoring Liquidware Stratusphere UX
Performance monitoring on Compellent arrays Fluid Cache performance monitoring Performance monitoring and capture at the ESXi host User experience monitoring on the virtual desktop
39 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 8 Software components
Software components Description Version
Dell Fluid Cache for SAN 20
Dell Compellent Storage Center 64
Dell Compellent Enterprise Manager 64
VMware Horizon View Server 60
VMware Horizon View Composer 60
VMware Horizon View Agent 60
VMware Horizon View Client 64-bit 60
VMware ESXi Hypervisor 55 U2
VMware vCenter Server 55 U2
Microsoft SQL Server 2008R2 Enterprise x64 105016001
Client VM OS Microsoft Windows 7 Enterprise x64 SP1
Management VM OS Microsoft Windows Server 2008 Enterprise R2 x64 SP1
Microsoft Office MS office 2010 Standard Service Pack 1
Login VSI Version 40
Iometer 20060727
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
32 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
641 Server host performance Similar to the standard user test statistics for the vSphere hosts were captured by using VMware vCenter
Server during the high IOPS (heavy user) test also There are no significant differences in CPU disk space
and network utilization between standard users and heavy users The storage adapter latency is also
showing similar on hosts and observed on Fluid Cache
642 User experience monitoring Figure 16 here shows the response time as experienced by each user as calculated by Login VSI for the
heavy user test The graph shows that the VSImax (Dynamic) value was 796 indicating that the solution is
capable of supporting the 800 user high IOPS desktops with 90 IOPSVM
Figure 16 Login VSI user experience monitoring for 800 user high IOPS desktops
33 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
643 High IOPS (heavy user) test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SAN based VDI solution is able to host 800 virtual desktops and support a
high user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only and less than 2
percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to easily handle this login storm with low latency Subsequently it was able to handle 72000 IOPS
at high IOPS steady state with 90 IOPSVM with a maximum of 75 msec latency
34 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
7 Best practices This section provides the best practices derived from the testing and analysis in Section 6
71 Virtual Desktop Infrastructure This section provides best practices for the implementation of VDI using Dell Fluid Cache for SAN
711 Implement roaming profiles and folder redirection Dell recommends that all users in the VDI environment be configured with roaming profiles and folder
redirection This preserves user profiles and user data across boots while using non-persistent virtual
desktops
Also Dell recommends to use a high performance file service to provide the profile and folder redirection
A separate array may be used to host these volumes for best performance
712 Boot and login storm considerations Section 62 demonstrated the Fluid Cache for SAN performance under boot storm To avoid any potential
IO bursts because of boot storm and degraded user experience and performances Dell recommends that
all or portion of desktops be prebooted Connection brokers such as VMware Horizon View provide the
functionality to configure number of standby desktops
713 Windows 7 master image for desktop VMs Dell recommends that the operating system be customized in order to provide the best performance in a
VDI environment This includes disabling some services which may not be required This can improve
performance for the end user VMware has a specific set of recommendations and settings for Windows 7
and Windows 8 that allow for faster logins quicker screen refreshes and generally better performance
The VMware recommendations for Windows 7 and Windows 8 image optimization can be found here
httpwwwvmwarecomresourcestechresources10157
714 VDI Management infrastructure recommendations Dell recommends to have redundancy and load balancing for all VDI management services in the case of
VMware Horizon View solution as tested here the vSphere Server VMware Horizon View Servers and SQL
Servers Ideally these should be running on clustered hosts with VMware vSphere DRS (distributed
resource scheduler) and HA (high availability) enabled
72 Server host The vSphere servers hosting the infrastructure service providers and the virtual desktops are
recommended to be configured as follows
35 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Follow VMware and Dell best practices for installing and configuring vSphere
Separate virtual switches to segregate iSCSI SAN traffic VDI traffic vMotion traffic and Management
network traffic
Each network path must be assigned to a minimum of two physical NICs for high availability
VMware Knowledge Base article about best practices for installing vSphere 55
httpkbvmwarecomkb2052329
73 Network layer Dell recommends that at least two physical NICs on each vSphere server be dedicated to the VDI network
Use VLANs to segregate different types of network traffic on the same physical network In this case Dell
recommends to separate the infrastructure vMotion and VDI LAN traffic in to separate VLANs
Do not use VLANs to segregate iSCSI SAN and Fluide Cache traffic It is required that SAN and Cache traffic
be on separate dedicated physical network to provide the best performance
Virtual switches in vSphere have a default limit of 120 ports If the number of virtual desktops on each host
exceeds the available ports vSwitch properties should be changed to support the required number of
virtual desktops This change requires a restart of the host vSphere server
On iSCSI SAN switches Spanning tree must be disabled on switch ports connected to end devices for
server and storage ports The PortFast setting must be enabled in the switch configuration for these ports
Jumbo frames and Flow control (if the NICs support it) should be enabled for all components of the iSCSI
network
More information about configuring Dell Networking switches for use with Dell Storage iSCSI SANs is
available here
httpencommunitydellcomtechcenterstoragewwiki4250switch-configuration-guides-by-sisaspx
74 Storage The Dell SC storage arrays combined with Fluid Cache is an excellent platform for providing cost-effective
performance in VDI environments
Fluid Cache for SAN extends the power of Compellent intelligent data placement from the SAN to the
server By providing a single infrastructure for data at both high- and low ends of the performance
spectrum Fluid Cache for SAN with Storage Center 65 array software eliminates the tradeoffs between
server performance and full-featured SAN benefits such as reliability manageability and data protection
Dell recommends to have separate volumes for base image and virtual desktops This enables better
manageability of the volumes easier performance monitoring and allows easy future growth
Dell recommends to use a separate high performance file service to provide file shares for roaming
profiles and user shares
36 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
8 Conclusion The technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed by using a Horizon View VDI platform leveraging Dell Fluid Cache for SAN The storage IO
characteristics under various VDI workload scenarios (boot storm login storm and steady state) along
with performance characteristics throughout the VDI stack (for example vSphere server performance and
user experience) demonstrate the optimal configuration of the infrastructure used for this VDI
deployment For more information about Fluid Cache contact your Dell account manager
37 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
A Horizon view solution configuration
Table 7 Hardware components
Hardware components Description
Virtual Desktops 4 timesDell PowerEdge R720 Servers (Fluid Cache Providers)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
2times350 GB Dell Express Flash PCIe SSDs
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
4 x Dell PowerEdge R720 Servers (Fluid Cache Clients)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55 U2 on all R720 servers Windows 7 (64 Bit) VMs
Infrastructure Servers 2 x Dell PowerEdge R720 servers
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
96 GB RAM
2times300 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55U2 on all R720 servers VMs are loaded with Microsoft Windows 2008 R2
Active Directory
VMware Horizon View 60 Server 1
VMware Horizon View 60 Server 2
VMware vCenter Server 55 update 2
VMware Horizon View Composer
SQL Server
File Server
Login VSI Launchers 8 x Dell PowerEdge M610 servers
2timesIntelreg Xeonreg E-5503 200 GHz Processors
16 GB RAM
4times146 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57711 10GbE NIC
ESXi 51 installed on all R810 servers VMs are loaded with Microsoft Windows 7 64bit Each VM supports up to 30 Login VSI launcher sessions
38 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Network Management VDI LAN
1timesDell Force10 S55 1Gb Ethernet Switch
iSCSI SAN
1timesDell Force10 S4810 10Gb Ethernet Switch
Cache network
1timesDell Force10 S4810 10Gb Ethernet Switch
One Force10 S4810 switch might suffice for all the cache iSCSI SAN VDI LAN and management traffic
Storage 2timesDell Compellent SC8000 controllers 4times6Gb SAS 4-port PCI-E Full-height cards for back-end connectivity 2times10Gb iSCSI 2 port PCI-E Low-profile IO cards for front end connectivity 1timesDell Compellent SC200 disk enclosures 12times4TB NL-SAS 6Gb 72K 35rdquo drives
User Data Infrastructure VMs Virtual Desktops
Performance Monitoring
Dell Compellent Enterprise Manager Dell Fluid Cache for SAN performance monitoring tool () vCenter Performance monitoring Liquidware Stratusphere UX
Performance monitoring on Compellent arrays Fluid Cache performance monitoring Performance monitoring and capture at the ESXi host User experience monitoring on the virtual desktop
39 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 8 Software components
Software components Description Version
Dell Fluid Cache for SAN 20
Dell Compellent Storage Center 64
Dell Compellent Enterprise Manager 64
VMware Horizon View Server 60
VMware Horizon View Composer 60
VMware Horizon View Agent 60
VMware Horizon View Client 64-bit 60
VMware ESXi Hypervisor 55 U2
VMware vCenter Server 55 U2
Microsoft SQL Server 2008R2 Enterprise x64 105016001
Client VM OS Microsoft Windows 7 Enterprise x64 SP1
Management VM OS Microsoft Windows Server 2008 Enterprise R2 x64 SP1
Microsoft Office MS office 2010 Standard Service Pack 1
Login VSI Version 40
Iometer 20060727
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
33 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
643 High IOPS (heavy user) test results summary The key observations from the test results are listed here
The Dell Fluid Cache for SAN based VDI solution is able to host 800 virtual desktops and support a
high user type of IO activity
The VDI IO was mostly write-intensive IO with more than 98 percent write-only and less than 2
percent read-only operations
None of the system resources on the vSphere servers hosting the virtual desktops reached
maximum utilization levels at any time
When 800 users were logged in within 20 minutes the Fluid Cache for SAN VDI solution was able
to easily handle this login storm with low latency Subsequently it was able to handle 72000 IOPS
at high IOPS steady state with 90 IOPSVM with a maximum of 75 msec latency
34 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
7 Best practices This section provides the best practices derived from the testing and analysis in Section 6
71 Virtual Desktop Infrastructure This section provides best practices for the implementation of VDI using Dell Fluid Cache for SAN
711 Implement roaming profiles and folder redirection Dell recommends that all users in the VDI environment be configured with roaming profiles and folder
redirection This preserves user profiles and user data across boots while using non-persistent virtual
desktops
Also Dell recommends to use a high performance file service to provide the profile and folder redirection
A separate array may be used to host these volumes for best performance
712 Boot and login storm considerations Section 62 demonstrated the Fluid Cache for SAN performance under boot storm To avoid any potential
IO bursts because of boot storm and degraded user experience and performances Dell recommends that
all or portion of desktops be prebooted Connection brokers such as VMware Horizon View provide the
functionality to configure number of standby desktops
713 Windows 7 master image for desktop VMs Dell recommends that the operating system be customized in order to provide the best performance in a
VDI environment This includes disabling some services which may not be required This can improve
performance for the end user VMware has a specific set of recommendations and settings for Windows 7
and Windows 8 that allow for faster logins quicker screen refreshes and generally better performance
The VMware recommendations for Windows 7 and Windows 8 image optimization can be found here
httpwwwvmwarecomresourcestechresources10157
714 VDI Management infrastructure recommendations Dell recommends to have redundancy and load balancing for all VDI management services in the case of
VMware Horizon View solution as tested here the vSphere Server VMware Horizon View Servers and SQL
Servers Ideally these should be running on clustered hosts with VMware vSphere DRS (distributed
resource scheduler) and HA (high availability) enabled
72 Server host The vSphere servers hosting the infrastructure service providers and the virtual desktops are
recommended to be configured as follows
35 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Follow VMware and Dell best practices for installing and configuring vSphere
Separate virtual switches to segregate iSCSI SAN traffic VDI traffic vMotion traffic and Management
network traffic
Each network path must be assigned to a minimum of two physical NICs for high availability
VMware Knowledge Base article about best practices for installing vSphere 55
httpkbvmwarecomkb2052329
73 Network layer Dell recommends that at least two physical NICs on each vSphere server be dedicated to the VDI network
Use VLANs to segregate different types of network traffic on the same physical network In this case Dell
recommends to separate the infrastructure vMotion and VDI LAN traffic in to separate VLANs
Do not use VLANs to segregate iSCSI SAN and Fluide Cache traffic It is required that SAN and Cache traffic
be on separate dedicated physical network to provide the best performance
Virtual switches in vSphere have a default limit of 120 ports If the number of virtual desktops on each host
exceeds the available ports vSwitch properties should be changed to support the required number of
virtual desktops This change requires a restart of the host vSphere server
On iSCSI SAN switches Spanning tree must be disabled on switch ports connected to end devices for
server and storage ports The PortFast setting must be enabled in the switch configuration for these ports
Jumbo frames and Flow control (if the NICs support it) should be enabled for all components of the iSCSI
network
More information about configuring Dell Networking switches for use with Dell Storage iSCSI SANs is
available here
httpencommunitydellcomtechcenterstoragewwiki4250switch-configuration-guides-by-sisaspx
74 Storage The Dell SC storage arrays combined with Fluid Cache is an excellent platform for providing cost-effective
performance in VDI environments
Fluid Cache for SAN extends the power of Compellent intelligent data placement from the SAN to the
server By providing a single infrastructure for data at both high- and low ends of the performance
spectrum Fluid Cache for SAN with Storage Center 65 array software eliminates the tradeoffs between
server performance and full-featured SAN benefits such as reliability manageability and data protection
Dell recommends to have separate volumes for base image and virtual desktops This enables better
manageability of the volumes easier performance monitoring and allows easy future growth
Dell recommends to use a separate high performance file service to provide file shares for roaming
profiles and user shares
36 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
8 Conclusion The technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed by using a Horizon View VDI platform leveraging Dell Fluid Cache for SAN The storage IO
characteristics under various VDI workload scenarios (boot storm login storm and steady state) along
with performance characteristics throughout the VDI stack (for example vSphere server performance and
user experience) demonstrate the optimal configuration of the infrastructure used for this VDI
deployment For more information about Fluid Cache contact your Dell account manager
37 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
A Horizon view solution configuration
Table 7 Hardware components
Hardware components Description
Virtual Desktops 4 timesDell PowerEdge R720 Servers (Fluid Cache Providers)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
2times350 GB Dell Express Flash PCIe SSDs
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
4 x Dell PowerEdge R720 Servers (Fluid Cache Clients)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55 U2 on all R720 servers Windows 7 (64 Bit) VMs
Infrastructure Servers 2 x Dell PowerEdge R720 servers
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
96 GB RAM
2times300 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55U2 on all R720 servers VMs are loaded with Microsoft Windows 2008 R2
Active Directory
VMware Horizon View 60 Server 1
VMware Horizon View 60 Server 2
VMware vCenter Server 55 update 2
VMware Horizon View Composer
SQL Server
File Server
Login VSI Launchers 8 x Dell PowerEdge M610 servers
2timesIntelreg Xeonreg E-5503 200 GHz Processors
16 GB RAM
4times146 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57711 10GbE NIC
ESXi 51 installed on all R810 servers VMs are loaded with Microsoft Windows 7 64bit Each VM supports up to 30 Login VSI launcher sessions
38 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Network Management VDI LAN
1timesDell Force10 S55 1Gb Ethernet Switch
iSCSI SAN
1timesDell Force10 S4810 10Gb Ethernet Switch
Cache network
1timesDell Force10 S4810 10Gb Ethernet Switch
One Force10 S4810 switch might suffice for all the cache iSCSI SAN VDI LAN and management traffic
Storage 2timesDell Compellent SC8000 controllers 4times6Gb SAS 4-port PCI-E Full-height cards for back-end connectivity 2times10Gb iSCSI 2 port PCI-E Low-profile IO cards for front end connectivity 1timesDell Compellent SC200 disk enclosures 12times4TB NL-SAS 6Gb 72K 35rdquo drives
User Data Infrastructure VMs Virtual Desktops
Performance Monitoring
Dell Compellent Enterprise Manager Dell Fluid Cache for SAN performance monitoring tool () vCenter Performance monitoring Liquidware Stratusphere UX
Performance monitoring on Compellent arrays Fluid Cache performance monitoring Performance monitoring and capture at the ESXi host User experience monitoring on the virtual desktop
39 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 8 Software components
Software components Description Version
Dell Fluid Cache for SAN 20
Dell Compellent Storage Center 64
Dell Compellent Enterprise Manager 64
VMware Horizon View Server 60
VMware Horizon View Composer 60
VMware Horizon View Agent 60
VMware Horizon View Client 64-bit 60
VMware ESXi Hypervisor 55 U2
VMware vCenter Server 55 U2
Microsoft SQL Server 2008R2 Enterprise x64 105016001
Client VM OS Microsoft Windows 7 Enterprise x64 SP1
Management VM OS Microsoft Windows Server 2008 Enterprise R2 x64 SP1
Microsoft Office MS office 2010 Standard Service Pack 1
Login VSI Version 40
Iometer 20060727
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
34 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
7 Best practices This section provides the best practices derived from the testing and analysis in Section 6
71 Virtual Desktop Infrastructure This section provides best practices for the implementation of VDI using Dell Fluid Cache for SAN
711 Implement roaming profiles and folder redirection Dell recommends that all users in the VDI environment be configured with roaming profiles and folder
redirection This preserves user profiles and user data across boots while using non-persistent virtual
desktops
Also Dell recommends to use a high performance file service to provide the profile and folder redirection
A separate array may be used to host these volumes for best performance
712 Boot and login storm considerations Section 62 demonstrated the Fluid Cache for SAN performance under boot storm To avoid any potential
IO bursts because of boot storm and degraded user experience and performances Dell recommends that
all or portion of desktops be prebooted Connection brokers such as VMware Horizon View provide the
functionality to configure number of standby desktops
713 Windows 7 master image for desktop VMs Dell recommends that the operating system be customized in order to provide the best performance in a
VDI environment This includes disabling some services which may not be required This can improve
performance for the end user VMware has a specific set of recommendations and settings for Windows 7
and Windows 8 that allow for faster logins quicker screen refreshes and generally better performance
The VMware recommendations for Windows 7 and Windows 8 image optimization can be found here
httpwwwvmwarecomresourcestechresources10157
714 VDI Management infrastructure recommendations Dell recommends to have redundancy and load balancing for all VDI management services in the case of
VMware Horizon View solution as tested here the vSphere Server VMware Horizon View Servers and SQL
Servers Ideally these should be running on clustered hosts with VMware vSphere DRS (distributed
resource scheduler) and HA (high availability) enabled
72 Server host The vSphere servers hosting the infrastructure service providers and the virtual desktops are
recommended to be configured as follows
35 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Follow VMware and Dell best practices for installing and configuring vSphere
Separate virtual switches to segregate iSCSI SAN traffic VDI traffic vMotion traffic and Management
network traffic
Each network path must be assigned to a minimum of two physical NICs for high availability
VMware Knowledge Base article about best practices for installing vSphere 55
httpkbvmwarecomkb2052329
73 Network layer Dell recommends that at least two physical NICs on each vSphere server be dedicated to the VDI network
Use VLANs to segregate different types of network traffic on the same physical network In this case Dell
recommends to separate the infrastructure vMotion and VDI LAN traffic in to separate VLANs
Do not use VLANs to segregate iSCSI SAN and Fluide Cache traffic It is required that SAN and Cache traffic
be on separate dedicated physical network to provide the best performance
Virtual switches in vSphere have a default limit of 120 ports If the number of virtual desktops on each host
exceeds the available ports vSwitch properties should be changed to support the required number of
virtual desktops This change requires a restart of the host vSphere server
On iSCSI SAN switches Spanning tree must be disabled on switch ports connected to end devices for
server and storage ports The PortFast setting must be enabled in the switch configuration for these ports
Jumbo frames and Flow control (if the NICs support it) should be enabled for all components of the iSCSI
network
More information about configuring Dell Networking switches for use with Dell Storage iSCSI SANs is
available here
httpencommunitydellcomtechcenterstoragewwiki4250switch-configuration-guides-by-sisaspx
74 Storage The Dell SC storage arrays combined with Fluid Cache is an excellent platform for providing cost-effective
performance in VDI environments
Fluid Cache for SAN extends the power of Compellent intelligent data placement from the SAN to the
server By providing a single infrastructure for data at both high- and low ends of the performance
spectrum Fluid Cache for SAN with Storage Center 65 array software eliminates the tradeoffs between
server performance and full-featured SAN benefits such as reliability manageability and data protection
Dell recommends to have separate volumes for base image and virtual desktops This enables better
manageability of the volumes easier performance monitoring and allows easy future growth
Dell recommends to use a separate high performance file service to provide file shares for roaming
profiles and user shares
36 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
8 Conclusion The technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed by using a Horizon View VDI platform leveraging Dell Fluid Cache for SAN The storage IO
characteristics under various VDI workload scenarios (boot storm login storm and steady state) along
with performance characteristics throughout the VDI stack (for example vSphere server performance and
user experience) demonstrate the optimal configuration of the infrastructure used for this VDI
deployment For more information about Fluid Cache contact your Dell account manager
37 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
A Horizon view solution configuration
Table 7 Hardware components
Hardware components Description
Virtual Desktops 4 timesDell PowerEdge R720 Servers (Fluid Cache Providers)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
2times350 GB Dell Express Flash PCIe SSDs
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
4 x Dell PowerEdge R720 Servers (Fluid Cache Clients)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55 U2 on all R720 servers Windows 7 (64 Bit) VMs
Infrastructure Servers 2 x Dell PowerEdge R720 servers
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
96 GB RAM
2times300 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55U2 on all R720 servers VMs are loaded with Microsoft Windows 2008 R2
Active Directory
VMware Horizon View 60 Server 1
VMware Horizon View 60 Server 2
VMware vCenter Server 55 update 2
VMware Horizon View Composer
SQL Server
File Server
Login VSI Launchers 8 x Dell PowerEdge M610 servers
2timesIntelreg Xeonreg E-5503 200 GHz Processors
16 GB RAM
4times146 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57711 10GbE NIC
ESXi 51 installed on all R810 servers VMs are loaded with Microsoft Windows 7 64bit Each VM supports up to 30 Login VSI launcher sessions
38 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Network Management VDI LAN
1timesDell Force10 S55 1Gb Ethernet Switch
iSCSI SAN
1timesDell Force10 S4810 10Gb Ethernet Switch
Cache network
1timesDell Force10 S4810 10Gb Ethernet Switch
One Force10 S4810 switch might suffice for all the cache iSCSI SAN VDI LAN and management traffic
Storage 2timesDell Compellent SC8000 controllers 4times6Gb SAS 4-port PCI-E Full-height cards for back-end connectivity 2times10Gb iSCSI 2 port PCI-E Low-profile IO cards for front end connectivity 1timesDell Compellent SC200 disk enclosures 12times4TB NL-SAS 6Gb 72K 35rdquo drives
User Data Infrastructure VMs Virtual Desktops
Performance Monitoring
Dell Compellent Enterprise Manager Dell Fluid Cache for SAN performance monitoring tool () vCenter Performance monitoring Liquidware Stratusphere UX
Performance monitoring on Compellent arrays Fluid Cache performance monitoring Performance monitoring and capture at the ESXi host User experience monitoring on the virtual desktop
39 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 8 Software components
Software components Description Version
Dell Fluid Cache for SAN 20
Dell Compellent Storage Center 64
Dell Compellent Enterprise Manager 64
VMware Horizon View Server 60
VMware Horizon View Composer 60
VMware Horizon View Agent 60
VMware Horizon View Client 64-bit 60
VMware ESXi Hypervisor 55 U2
VMware vCenter Server 55 U2
Microsoft SQL Server 2008R2 Enterprise x64 105016001
Client VM OS Microsoft Windows 7 Enterprise x64 SP1
Management VM OS Microsoft Windows Server 2008 Enterprise R2 x64 SP1
Microsoft Office MS office 2010 Standard Service Pack 1
Login VSI Version 40
Iometer 20060727
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
35 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Follow VMware and Dell best practices for installing and configuring vSphere
Separate virtual switches to segregate iSCSI SAN traffic VDI traffic vMotion traffic and Management
network traffic
Each network path must be assigned to a minimum of two physical NICs for high availability
VMware Knowledge Base article about best practices for installing vSphere 55
httpkbvmwarecomkb2052329
73 Network layer Dell recommends that at least two physical NICs on each vSphere server be dedicated to the VDI network
Use VLANs to segregate different types of network traffic on the same physical network In this case Dell
recommends to separate the infrastructure vMotion and VDI LAN traffic in to separate VLANs
Do not use VLANs to segregate iSCSI SAN and Fluide Cache traffic It is required that SAN and Cache traffic
be on separate dedicated physical network to provide the best performance
Virtual switches in vSphere have a default limit of 120 ports If the number of virtual desktops on each host
exceeds the available ports vSwitch properties should be changed to support the required number of
virtual desktops This change requires a restart of the host vSphere server
On iSCSI SAN switches Spanning tree must be disabled on switch ports connected to end devices for
server and storage ports The PortFast setting must be enabled in the switch configuration for these ports
Jumbo frames and Flow control (if the NICs support it) should be enabled for all components of the iSCSI
network
More information about configuring Dell Networking switches for use with Dell Storage iSCSI SANs is
available here
httpencommunitydellcomtechcenterstoragewwiki4250switch-configuration-guides-by-sisaspx
74 Storage The Dell SC storage arrays combined with Fluid Cache is an excellent platform for providing cost-effective
performance in VDI environments
Fluid Cache for SAN extends the power of Compellent intelligent data placement from the SAN to the
server By providing a single infrastructure for data at both high- and low ends of the performance
spectrum Fluid Cache for SAN with Storage Center 65 array software eliminates the tradeoffs between
server performance and full-featured SAN benefits such as reliability manageability and data protection
Dell recommends to have separate volumes for base image and virtual desktops This enables better
manageability of the volumes easier performance monitoring and allows easy future growth
Dell recommends to use a separate high performance file service to provide file shares for roaming
profiles and user shares
36 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
8 Conclusion The technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed by using a Horizon View VDI platform leveraging Dell Fluid Cache for SAN The storage IO
characteristics under various VDI workload scenarios (boot storm login storm and steady state) along
with performance characteristics throughout the VDI stack (for example vSphere server performance and
user experience) demonstrate the optimal configuration of the infrastructure used for this VDI
deployment For more information about Fluid Cache contact your Dell account manager
37 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
A Horizon view solution configuration
Table 7 Hardware components
Hardware components Description
Virtual Desktops 4 timesDell PowerEdge R720 Servers (Fluid Cache Providers)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
2times350 GB Dell Express Flash PCIe SSDs
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
4 x Dell PowerEdge R720 Servers (Fluid Cache Clients)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55 U2 on all R720 servers Windows 7 (64 Bit) VMs
Infrastructure Servers 2 x Dell PowerEdge R720 servers
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
96 GB RAM
2times300 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55U2 on all R720 servers VMs are loaded with Microsoft Windows 2008 R2
Active Directory
VMware Horizon View 60 Server 1
VMware Horizon View 60 Server 2
VMware vCenter Server 55 update 2
VMware Horizon View Composer
SQL Server
File Server
Login VSI Launchers 8 x Dell PowerEdge M610 servers
2timesIntelreg Xeonreg E-5503 200 GHz Processors
16 GB RAM
4times146 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57711 10GbE NIC
ESXi 51 installed on all R810 servers VMs are loaded with Microsoft Windows 7 64bit Each VM supports up to 30 Login VSI launcher sessions
38 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Network Management VDI LAN
1timesDell Force10 S55 1Gb Ethernet Switch
iSCSI SAN
1timesDell Force10 S4810 10Gb Ethernet Switch
Cache network
1timesDell Force10 S4810 10Gb Ethernet Switch
One Force10 S4810 switch might suffice for all the cache iSCSI SAN VDI LAN and management traffic
Storage 2timesDell Compellent SC8000 controllers 4times6Gb SAS 4-port PCI-E Full-height cards for back-end connectivity 2times10Gb iSCSI 2 port PCI-E Low-profile IO cards for front end connectivity 1timesDell Compellent SC200 disk enclosures 12times4TB NL-SAS 6Gb 72K 35rdquo drives
User Data Infrastructure VMs Virtual Desktops
Performance Monitoring
Dell Compellent Enterprise Manager Dell Fluid Cache for SAN performance monitoring tool () vCenter Performance monitoring Liquidware Stratusphere UX
Performance monitoring on Compellent arrays Fluid Cache performance monitoring Performance monitoring and capture at the ESXi host User experience monitoring on the virtual desktop
39 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 8 Software components
Software components Description Version
Dell Fluid Cache for SAN 20
Dell Compellent Storage Center 64
Dell Compellent Enterprise Manager 64
VMware Horizon View Server 60
VMware Horizon View Composer 60
VMware Horizon View Agent 60
VMware Horizon View Client 64-bit 60
VMware ESXi Hypervisor 55 U2
VMware vCenter Server 55 U2
Microsoft SQL Server 2008R2 Enterprise x64 105016001
Client VM OS Microsoft Windows 7 Enterprise x64 SP1
Management VM OS Microsoft Windows Server 2008 Enterprise R2 x64 SP1
Microsoft Office MS office 2010 Standard Service Pack 1
Login VSI Version 40
Iometer 20060727
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
36 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
8 Conclusion The technical white paper demonstrates how a high IOPS 800-user virtual desktop environment can be
deployed by using a Horizon View VDI platform leveraging Dell Fluid Cache for SAN The storage IO
characteristics under various VDI workload scenarios (boot storm login storm and steady state) along
with performance characteristics throughout the VDI stack (for example vSphere server performance and
user experience) demonstrate the optimal configuration of the infrastructure used for this VDI
deployment For more information about Fluid Cache contact your Dell account manager
37 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
A Horizon view solution configuration
Table 7 Hardware components
Hardware components Description
Virtual Desktops 4 timesDell PowerEdge R720 Servers (Fluid Cache Providers)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
2times350 GB Dell Express Flash PCIe SSDs
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
4 x Dell PowerEdge R720 Servers (Fluid Cache Clients)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55 U2 on all R720 servers Windows 7 (64 Bit) VMs
Infrastructure Servers 2 x Dell PowerEdge R720 servers
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
96 GB RAM
2times300 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55U2 on all R720 servers VMs are loaded with Microsoft Windows 2008 R2
Active Directory
VMware Horizon View 60 Server 1
VMware Horizon View 60 Server 2
VMware vCenter Server 55 update 2
VMware Horizon View Composer
SQL Server
File Server
Login VSI Launchers 8 x Dell PowerEdge M610 servers
2timesIntelreg Xeonreg E-5503 200 GHz Processors
16 GB RAM
4times146 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57711 10GbE NIC
ESXi 51 installed on all R810 servers VMs are loaded with Microsoft Windows 7 64bit Each VM supports up to 30 Login VSI launcher sessions
38 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Network Management VDI LAN
1timesDell Force10 S55 1Gb Ethernet Switch
iSCSI SAN
1timesDell Force10 S4810 10Gb Ethernet Switch
Cache network
1timesDell Force10 S4810 10Gb Ethernet Switch
One Force10 S4810 switch might suffice for all the cache iSCSI SAN VDI LAN and management traffic
Storage 2timesDell Compellent SC8000 controllers 4times6Gb SAS 4-port PCI-E Full-height cards for back-end connectivity 2times10Gb iSCSI 2 port PCI-E Low-profile IO cards for front end connectivity 1timesDell Compellent SC200 disk enclosures 12times4TB NL-SAS 6Gb 72K 35rdquo drives
User Data Infrastructure VMs Virtual Desktops
Performance Monitoring
Dell Compellent Enterprise Manager Dell Fluid Cache for SAN performance monitoring tool () vCenter Performance monitoring Liquidware Stratusphere UX
Performance monitoring on Compellent arrays Fluid Cache performance monitoring Performance monitoring and capture at the ESXi host User experience monitoring on the virtual desktop
39 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 8 Software components
Software components Description Version
Dell Fluid Cache for SAN 20
Dell Compellent Storage Center 64
Dell Compellent Enterprise Manager 64
VMware Horizon View Server 60
VMware Horizon View Composer 60
VMware Horizon View Agent 60
VMware Horizon View Client 64-bit 60
VMware ESXi Hypervisor 55 U2
VMware vCenter Server 55 U2
Microsoft SQL Server 2008R2 Enterprise x64 105016001
Client VM OS Microsoft Windows 7 Enterprise x64 SP1
Management VM OS Microsoft Windows Server 2008 Enterprise R2 x64 SP1
Microsoft Office MS office 2010 Standard Service Pack 1
Login VSI Version 40
Iometer 20060727
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
37 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
A Horizon view solution configuration
Table 7 Hardware components
Hardware components Description
Virtual Desktops 4 timesDell PowerEdge R720 Servers (Fluid Cache Providers)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
2times350 GB Dell Express Flash PCIe SSDs
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
4 x Dell PowerEdge R720 Servers (Fluid Cache Clients)
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
192 GB RAM
1 Connect-X3 card
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55 U2 on all R720 servers Windows 7 (64 Bit) VMs
Infrastructure Servers 2 x Dell PowerEdge R720 servers
2timesIntelreg Xeonreg E5-2680 29 GHz Processors
96 GB RAM
2times300 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57810 10GbE NIC
ESXi 55U2 on all R720 servers VMs are loaded with Microsoft Windows 2008 R2
Active Directory
VMware Horizon View 60 Server 1
VMware Horizon View 60 Server 2
VMware vCenter Server 55 update 2
VMware Horizon View Composer
SQL Server
File Server
Login VSI Launchers 8 x Dell PowerEdge M610 servers
2timesIntelreg Xeonreg E-5503 200 GHz Processors
16 GB RAM
4times146 GB 10K SAS internal disk drives
1timesDual-port Broadcom NetXtreme II 57711 10GbE NIC
ESXi 51 installed on all R810 servers VMs are loaded with Microsoft Windows 7 64bit Each VM supports up to 30 Login VSI launcher sessions
38 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Network Management VDI LAN
1timesDell Force10 S55 1Gb Ethernet Switch
iSCSI SAN
1timesDell Force10 S4810 10Gb Ethernet Switch
Cache network
1timesDell Force10 S4810 10Gb Ethernet Switch
One Force10 S4810 switch might suffice for all the cache iSCSI SAN VDI LAN and management traffic
Storage 2timesDell Compellent SC8000 controllers 4times6Gb SAS 4-port PCI-E Full-height cards for back-end connectivity 2times10Gb iSCSI 2 port PCI-E Low-profile IO cards for front end connectivity 1timesDell Compellent SC200 disk enclosures 12times4TB NL-SAS 6Gb 72K 35rdquo drives
User Data Infrastructure VMs Virtual Desktops
Performance Monitoring
Dell Compellent Enterprise Manager Dell Fluid Cache for SAN performance monitoring tool () vCenter Performance monitoring Liquidware Stratusphere UX
Performance monitoring on Compellent arrays Fluid Cache performance monitoring Performance monitoring and capture at the ESXi host User experience monitoring on the virtual desktop
39 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 8 Software components
Software components Description Version
Dell Fluid Cache for SAN 20
Dell Compellent Storage Center 64
Dell Compellent Enterprise Manager 64
VMware Horizon View Server 60
VMware Horizon View Composer 60
VMware Horizon View Agent 60
VMware Horizon View Client 64-bit 60
VMware ESXi Hypervisor 55 U2
VMware vCenter Server 55 U2
Microsoft SQL Server 2008R2 Enterprise x64 105016001
Client VM OS Microsoft Windows 7 Enterprise x64 SP1
Management VM OS Microsoft Windows Server 2008 Enterprise R2 x64 SP1
Microsoft Office MS office 2010 Standard Service Pack 1
Login VSI Version 40
Iometer 20060727
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
38 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Network Management VDI LAN
1timesDell Force10 S55 1Gb Ethernet Switch
iSCSI SAN
1timesDell Force10 S4810 10Gb Ethernet Switch
Cache network
1timesDell Force10 S4810 10Gb Ethernet Switch
One Force10 S4810 switch might suffice for all the cache iSCSI SAN VDI LAN and management traffic
Storage 2timesDell Compellent SC8000 controllers 4times6Gb SAS 4-port PCI-E Full-height cards for back-end connectivity 2times10Gb iSCSI 2 port PCI-E Low-profile IO cards for front end connectivity 1timesDell Compellent SC200 disk enclosures 12times4TB NL-SAS 6Gb 72K 35rdquo drives
User Data Infrastructure VMs Virtual Desktops
Performance Monitoring
Dell Compellent Enterprise Manager Dell Fluid Cache for SAN performance monitoring tool () vCenter Performance monitoring Liquidware Stratusphere UX
Performance monitoring on Compellent arrays Fluid Cache performance monitoring Performance monitoring and capture at the ESXi host User experience monitoring on the virtual desktop
39 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 8 Software components
Software components Description Version
Dell Fluid Cache for SAN 20
Dell Compellent Storage Center 64
Dell Compellent Enterprise Manager 64
VMware Horizon View Server 60
VMware Horizon View Composer 60
VMware Horizon View Agent 60
VMware Horizon View Client 64-bit 60
VMware ESXi Hypervisor 55 U2
VMware vCenter Server 55 U2
Microsoft SQL Server 2008R2 Enterprise x64 105016001
Client VM OS Microsoft Windows 7 Enterprise x64 SP1
Management VM OS Microsoft Windows Server 2008 Enterprise R2 x64 SP1
Microsoft Office MS office 2010 Standard Service Pack 1
Login VSI Version 40
Iometer 20060727
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
39 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Table 8 Software components
Software components Description Version
Dell Fluid Cache for SAN 20
Dell Compellent Storage Center 64
Dell Compellent Enterprise Manager 64
VMware Horizon View Server 60
VMware Horizon View Composer 60
VMware Horizon View Agent 60
VMware Horizon View Client 64-bit 60
VMware ESXi Hypervisor 55 U2
VMware vCenter Server 55 U2
Microsoft SQL Server 2008R2 Enterprise x64 105016001
Client VM OS Microsoft Windows 7 Enterprise x64 SP1
Management VM OS Microsoft Windows Server 2008 Enterprise R2 x64 SP1
Microsoft Office MS office 2010 Standard Service Pack 1
Login VSI Version 40
Iometer 20060727
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
40 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B vSphere host network configuration
Each vSphere host was configured with four virtual switches - vSwitch0 vSwitch1 vSwitch2 and vSwitch3
B1 vSwitch ndash Management traffic
vSwitch0 provides connection paths for all management LAN traffic The first partition of the physical
adapters from the two on-board NICs (Fabric A) was assigned to this switch
Figure 17 vSwitch0 ndash Management LAN
B2 vSwitch - iSCSI
Two partitions from the physical adapters in Fabric A are assigned to this virtual switch This vSwitch
carries the traffic required to provide VMware vMotion services
Figure 18 vSwitch1 ndash vMotion LAN
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
41 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
B3 vSwitch ndash Fluid Cache network
This virtual switch provided paths for all the iSCSI SAN traffic Two partitions of the physical adapters from
the two on-board NICS (Fabric A) were assigned to this virtual switch
Figure 19 vSwitch2 ndash iSCSI virtual switch
B4 vSwitch3
Two 10 GB physical adapters in Fabric B are assigned to this virtual switch This vSwitch carried all network
traffic for the VDI LAN
Figure 20 vSwitch3 ndash VDI LAN
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
42 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Additional resources
- Supportdellcom is focused on meeting your needs with proven services and support
- DellTechCentercom is an IT Community where you can connect with Dell Customers and Dell employees to
share knowledge best practices and information about Dell products and your installations
- Referenced or recommended Dell publications
- The following VMware publications are referenced in this document are recommended sources of additional
information
Additional Fluid Cache information at
httpwwwdellcomfluidcache
VMware Horizon View 60 documentation
httpspubsvmwarecomhorizon-view-60indexjsp
VMware Horizon View 60 Release notes
httpswwwvmwarecomsupporthorizon-viewdochorizon-view-602-release-noteshtml
VMware View Optimization Guide for Windows 7
httpwwwvmwarecomresourcestechresources10157
VMware KB article on best practices for installing vSphere 55
httpkbvmwarecomkb2052329
VMware blog entry on Optimizing Storage with View Storage Accelerator
httpblogsvmwarecomeuc201205optimizing-storage-with-view-storage-acceleratorhtml
VMware blog entry on View Storage Accelerator ndash In Practice
httpblogsvmwarecomeuc201205view-storage-accelerator-in-practicehtml
For Dell Storage best practices technical white papers reference architectures and sizing guidelines for
enterprise applications and SANs refer to Storage Infrastructure and Solutions Team Publications at
httpencommunitydellcomtechcenterextrasmwhite_papers20437942download
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom
43 Virtual Desktop Infrastructure with Dell Fluid Cache for SAN
Acknowledgements
This VDI reference architecture technical white paper is authored by the following members of the Dell
team
Kishore Gagrani Gordon Bookless Yinglong Jiang Chhandomay Mandal Paul Wynne Damon Zaylskie
Special thanks to Shawn Vasanth and Suresh
Shawn Salisbury D Vasanth Suresh Jasrasaria
Feedback
We encourage readers of this Dell technical white paper to provide feedback about the quality and
usefulness of this information by sending an email to Kishore_GagraniDellcom
Kishore_GagraniDellcom