Storage Decisions 2012 | © TechTarget
Randy Kerns
Senior Strategist
Evaluator Group
21st Century Storage –
What’s New and
What’s Changing
Overview
● New technologies in storage
- Continued evolution
- Each has great economic value
- Differing adoption rates
- Some require operational changes
● Vendors offering solutions
- Differences vary
- Some vendors are slow to deliver
May have a intermediate solution first
Storage Decisions 2012 | © TechTarget
Technologies Covered Here
● Solid-state technology
● Scale-out storage systems
● Storage virtualization disk virtualization
- Includes storage pooling, thin provisioning, device
protection
● Storage systems with storage as an application
● Object-based storage
Storage Decisions 2012 | © TechTarget
Evaluator Group view as the most important …currently:
Storage Decisions 2012 | © TechTarget
Overview
Solid-State Technology
Solid-State Technology
● Multiple implementations
- DRAM-based: uses battery to
retain state
- NAND – FLASH
SLC: single level cell: 1 or 0,
100,000’s of writes
MLC: multiple level cell: 3 or 4
states, 10,000’s of writes
Wear-leveling to balance usage
across cells
ECC used for correction of
single and double bit errors
● PCM: phase change
memory – future
Storage Decisions 2012 | © TechTarget
Solid-State Technology
● Usages
- SSD: Solid-state device,
Solid-state disk or drive
- Flash memory cards for
servers
- Tiering in storage systems
- Caching in storage systems
- All solid state storage systems
- Consumer
Storage Decisions 2012 | © TechTarget
Solid-State Device Usage
● Justifications for SSDs
- Rugged – no moving parts
- Performance – no rotational latency or actuator movement
as with HDDs
- Reliability – MTBF: typically 6x over HDD
- Operational costs – power requirement is typically 1/4th of
HDD
Storage Decisions 2012 | © TechTarget
Solid-State Devices in Storage
● General forms
- As HDD replacement in existing storage system architecture
HDD form factor
Connected with storage interface – Fibre Channel, SAS, SATA
For server, still requires HBA
- Memory extension – add-in card to the server or system on
PCIe Bus (called Flash card)
- PCIe-SSD (or SSS) – solid state device that connects to PCIe
bus via extender adapter
● Trend – data reduction in SSDs
- Compression & deduplication to multiply capacity
- New techniques will drive towards price parity with HDDs
Storage Decisions 2012 | © TechTarget
Solid-State Devices in Storage
● All SSD systems
- Storage platforms that only use SSDs
- Can be designed with only SSD
Optimize for performance and data placement – equal wear out
Consideration different with compression and deduplication vs.
storage systems with spinning disks
- Some traditional disk system vendors will sell systems with
only SSDs installed
Still have design considerations for spinning disks
- Many new vendors
A great deal to learn about storage, reliability, availability,
support, etc.
Each try to feature something “new”
Storage Decisions 2012 | © TechTarget
All SSD System Vendors
● PureStorage
● Nimbus
● Nimble Data
● Whiptail
● Nexgen
● Solid Fire
● Texas Memory Systems
● Violin
● Kaminario
● Virident
● CacheIQ
Storage Decisions 2012 | © TechTarget
Solid-State Devices
High-Performance
Disks
High-Capacity
Disks Data
Mo
vem
en
t
● In-the-box tiering
Major performance
boost
Limit economic
impact of costs of
higher performance
drives
Utilizes resources
better
Storage System Tiering “Within-the-Box
Storage Decisions 2012 | © TechTarget
Tiering vs. Caching
● Storage tiers
- Implies a particular price and performance metric
- Provides actual capacity
- All content resides on media
- Performance is limited only to media speed
- May be improved with caching
- Major gain: storage consolidation
● Caching
- Not considered actual storage
- All capacity must be backed by non-volatile media
- Performance limited to size of cache
- Limited use for random workloads
Actual
location
for data
Data is
transient
Storage Decisions 2012 | © TechTarget
Storage Decisions 2012 | © TechTarget
File and Block
Scale-Out Storage
Scale-Out Storage: Benefits
● Historically, storage systems scaled up by adding more
storage devices
- Created imbalance of access density IOPS/GB
- Economic choice created administrative challenge
● Scale-out technologies added more performance along
with capacity
- More control function - controllers
Storage Decisions 2012 | © TechTarget
Scale-Out vs. Scale Up
Storage Decisions 2012 | © TechTarget
Scale-Out Storage: File Storage
● Scale-out NAS
- Implemented using distributed file system usually
Clustered hardware
Global namespace across nodes
- Key implementation points
Linkage between nodes – InfiniBand, Ethernet:10Gb
I/O balancing between nodes
Capacity balancing between nodes
Coherency – across distance
Switching requirements
Storage Decisions 2012 | © TechTarget
Scale-Out NAS Vendors
● Dell FS7600 / FS8600
● EMC Isilon
● HP StoreAll X9000
● HDS HNAS
● IBM SONAS
● NetApp FAS 8.1.1
● Xyratex ClusterStor
● And others
Storage Decisions 2012 | © TechTarget
Scale-Out Storage: Block Storage
● Two approaches used
- Multiple controller cards to common backend storage
device pools
Backplane connected typically
Normally associated with high-end enterprise systems
- Federation of separate controller nodes (included with NAS
systems in some cases as integrated unified storage)
Complexities in cache coherency and I/O routing
Vendor differences
Storage Decisions 2012 | © TechTarget
Scale-Out Block Storage Vendors
● Data Direct Networks
● Dell EqualLogic
● HP Lefthand P4000
● IBM XIV
● And others
Storage Decisions 2012 | © TechTarget
Storage Decisions 2012 | © TechTarget
Disk Virtualization and Thin Provisioning
Storage Virtualization
Storage Virtualization: Disk Virtualization
● Recent storage system architecture
- Use storage pooling concept – carve up device resources
into smaller granular segments (typically called chunks)
- Allows new or more efficient operation
Finer grained allocation of capacity
Enables thin provisioning
Allows new, selectable data protection
Leads to great capacity proficiency
- Newly designed storage systems
- Added to older system designs
Storage Decisions 2012 | © TechTarget
Thin Provisioning
● Change in storage system design to allocation space only
on write
● Historically committed entire volume (LUN) to operating
system for use
- All capacity allocated
- Operating system or application used space as needed and
managed the space
- Led to inefficiencies – not all space for volumes was utilized
Storage Decisions 2012 | © TechTarget
Unused
Capacity
Used
Capacity
Volume/LUN
Traditional Allocation
Trapped
and
unavailable
for other
uses
Fully
Allocated
Typical Allocation
Storage Decisions 2012 | © TechTarget
Disk Virtualization
● When RAID added to storage, storage architecture was
changed to use data from stripes across drives in RAID
group
- Parity within the RAID group
- Distribution of data – wide striping – was based on number
of disks in RAID group
● Still have capacity efficiency issue
- Volumes with trapped capacity
Storage Decisions 2012 | © TechTarget
0 1 2 3 P
LUN 1 LUN 2 LUN 3 LUN 4 . . . .
RAID
Stripe
LUN Assigned From
Stripes in RAID Group
Physical Disk
Drives
RAID Group Example: RAID 5
4+1 (Data and Parity)
RAID Group Volumes
Storage Decisions 2012 | © TechTarget
Available
Used
Capacity
Used
Capacity
Available
Used
Capacity Used
Capacity
Available
LUN 2 LUN 1 LUN 3 LUN 4
Used
Available
Thinly Provisioned Volumes
Thin Provisioning Trapped Capacity
Storage Decisions 2012 | © TechTarget
Disk Virtualization
● Storage system architecture to only assign capacity as it
was written – some systems have had for some time but
not fully utilized
● Creates storage pools
- Set of chunks of data – size of chunk could be specified at
time of configuration
- Volumes were created without assigning real capacity
- As data written, chunks were assigned
● For modern architecture, chunks were distributed across
physical disks to match data protection choices
- Different RAID levels
- Advanced data protection techniques
Storage Decisions 2012 | © TechTarget
. . . .
Storage Pool
. . . . Physical
Disks
Chunks
Chunks added as required
Storage Decisions 2012 | © TechTarget
Storage Pooling
Thin Provisioned LUN
. . . .
Storage Pool
. . . . Physical
Disks
Chunks
mapped to
specific
physical
devices
Protection
of Chunks
Chunks
Chunks added as required
Thin Provisioned LUN
Storage Decisions 2012 | © TechTarget
Storage Pooling with Data Protection Across Pool
Thin Provisioning
● When space in volume is no longer required, data is
deleted
- For example: space can be returned to storage pool –
called space reclamation
● Different approaches for space reclamation
- Storage system scans for zero blocks and returns those
- APIs with applications and file systems to send UNMAP
SCSI command to storage system to release space
- Administrator copies volume that has grown “fat” to another
thin volume to return to thin state
Storage Decisions 2012 | © TechTarget
Forward Error Correction
● The RAID problem
- Large capacity disk drives take a long time to rebuild
● Potentially days
● Probability of a second error occurring is high – loss of data
Forward Error Correction
● The RAID problem - continued
- Multiple parity disks being utilized
● Complexity – management and algorithms
● How many should be used as capacity gets larger?
- Information is being distributed to multiple locations
● Does RAID work with multi-site locations?
● How much protection is required?
Forward Error Correction
● New approach for data protection
- For failed drives
- For locations that don’t respond when geographically dispersed
● Information Dispersal Algorithms or IDA
- Study area in computer science
- Early implementations from different sources – no large scale
adoption
- More correct term is Forward Error Correction
- Also Erasure Codes is used based on the details of
implementation
Forward Error Correction
● Selectivity on the amount of data protection
- Example: 12 of 16 drives must be present – tolerate loss of 4
- Example: 12 of 16 sites must respond with date – tolerate 4 sites not responding
- Important characteristic is the ability to set the protection level
● Potential benefit
- Disk system with protection set calculated for lifespan of storage system
- Failures tolerated over time – no replacements expected (with warning and exception conditions)
- No service planned ● Reduces warranty cost for vendor
● Reduces service interruption / impact for IT
Forward Error Correction
● Current products with Forward Error Correction
implementations
- EMC Isilon
- Amplidata
- Cleversafe
- EMC Atmos
- Scality
- NEC HydraStor
- DataDirect Networks Web Object Scaler
● Expect others – this will become a competitive area
Storage Decisions 2012 | © TechTarget
Storage as an Application
Storage Systems
Hypervisor within the Storage System
● Most storage systems hardware uses standard processor
technology
● New: Use of hypervisor in storage system
- Allows for multiple personalities
● Changes dynamic of storage system
- Run embedded storage system software as an application
Block storage control software
NAS software – file system – clustered, distributed, single
- Can run additional features as applications – example is
replication software
- Can run application software on storage system
Storage Decisions 2012 | © TechTarget
Advanced Storage System
Storage Decisions 2012 | © TechTarget
Hypervisor
Device
Blo
ck
Sto
rag
e
File S
tora
ge
Rep
lic
ati
on
Ap
pli
ca
tio
n
Ap
pli
cati
on
Storage Decisions 2012 | © TechTarget
Object-based Storage
Object-based Storage
● Renewed interest in object-based storage
● First very successful product was Centera
- Used content address as object ID
● New solutions developing
- Most use REST and HTTP for communication
- Generally best described as files with additional metadata
is the object
Storage Decisions 2012 | © TechTarget
Object-based Storage
● Storage systems designed that can store and retrieve
objects
● Reasons:
- Ability to manage more objects than standard file systems
- Additional information – metadata – aids in characterization
of information
Controls such as protection requirements, retention periods,
other useful information
● Standards exist for object-based storage
- Not necessarily completely followed
● Applications must change to use object-based storage
Storage Decisions 2012 | © TechTarget
Object Storage System
Storage Decisions 2012 | © TechTarget
Application Network Object
Storage
System
HTTP /
REST
Objects
Metadata
Typically
10GbE
File
Attributes
File
Storage Data &
Attributes
Object
Storage
(local or
Cloud)
CIFS, NFS HTTP
REST/CD
MI
Adds Metadata
Administrator Defined
Object Storage Vendors
● Amplidata
● Data Direct Networks Web Object Scaler
● Dell DX
● EMC Centera
● HDS Hitachi Content Platform
● Others – including cloud locations such as Amazon S3
Storage Decisions 2012 | © TechTarget
Summary
● Storage systems are changing
- New capabilities
● Storage as an application – running in a virtual machine
● Virtual machines within storage systems
- New architectures
● Storage pooling in disk virtualization
● Thin provisioning
● Technology will cause more changes
- Solid state technology
- Tiering & caching
- Object based storage
● More options, better opportunities and choices
Storage Decisions 2012 | © TechTarget
Storage Decisions 2012 | © TechTarget
Randy Kerns: [email protected]
Twitter: @rgkerns
Blog: http://itknowledgeexchange.techtarget.com/storage-soup/
Thank You! Questions?