Hypervisor-Based QoS Helps with the symptoms but by itself not the cure
Adam Carter, Director of Product Management
Agenda • Hypervisor-based approach is good, but not the total solution
• Storage is a necessary party in QoS discussion
• Ideally hypervisor layer sets and manages the QoS policy and storage system enforces it
• Unfortunately, not all storage QoS is created equal
What are we trying to avoid?
• Few resource hungry applications negatively affect all other volume performance
Traditional Multi-Tenant Performance
Noisy Neighbor
Hypervisor-based QoS
• Helps address some of the performance variability of virtual machines
• But hypervisor has very little control or visibility of the underlying storage system resources
• An environment that depends on predictable performance demands a more coordinated approach across both host and storage resources
ADD SOME SOIC or hypervisor-based picture
Key limitations of hypervisor-centric approach to QoS
• Lack of IOPS control
• Performance Degradation
• Forced Overprovisioning
• Lacking Coordination
• Inability to set IOPS minimums
• Limited functionality
Lack of IOPS Control
• Hypervisor can throttle IOPS, but it has no control over maintaining the total IOP pool available
• W/o governance from underlying storage there is no way for a hypervisor to guarantee a minimum IOP level
• Hypervisor will always be at the mercy of the storage device.
PerformanceDegradation
• Without visibility into back-end storage, there is no way for the hypervisor to know what resources remain available to it
• As storage system utilization increases performance degradation becomes a real concern
• With virtual resources contending for the same pool of storage resources, the lack of isolation creates an IOPS free-for-all.
• This performance variability is a non-starter for a multi-tenant infrastructure hosting performance sensitive applications.
Forced Over-Provisioning
• Only way to ensure a large enough IOPS pool for these VMs is to extensively overprovision your storage.
• Underutilization kills economics of shared storage environment
Lacking Coordination
• Throttling IOP usage to VMs is a basic form of storage QoS
• Lacks end-to-end coordination and orchestration between the host and the underlying storage system
• Coordination helps ensure each VM has the resources it needs to properly support the application.
Inability to set IOPS minimums
• Can cap performance
• Can prioritize relative to other apps
• But w/o minimum IOPS settings you can’t guarantee any level of performance to a specific application
SIOC Limitations
• Doesn’t work with RDM
• Not supported with extents
• Can’t be managed by multiple vCenter servers
• Lack of compatibility with auto-tiering
So what does the future hold?
• Forthcoming API integrations between hypervisors and storage (i.e. VVOLs) will provide a more holistic approach to managing QoS
• End-to-end QoS dependent on enforcement across the storage infrastructure
Not all storage QoS is created equal
• Prioritization– Cannot guarantee any app actually gets
the performance it needs
• Rate limiting– No concept or capability for guaranteeing
minimum levels of performance
• Tiered Storage– Combines multiple types of media to deliver different
performance levels
– Performance for every application varies as algorithms move data between media
QoS is not a feature, it’s an architecture!
Purpose-built for QoS
• All-SSD Platform – Deliver consistent latency for every IO
• True Scale-out Architecture– Linear performance gains as system scales
• RAID-less Data Protection– Predictable performance in any failure condition
• Balanced Load Distribution– Eliminate hot spots that create unpredictable IO latency
• Fine-grain Quality of Service Control– Guarantee volume performance
• Performance Virtualization– Deliver performance resources independent of capacity
and on demand
Begin with the end in mind
• Applications allocated into performance tiers
• Changes are immediate can be made on the fly
Traditional Multi-Tenant Performance
Application of SolidFire QoS controls
1620 Pearl Street,Boulder, Colorado 80302
Phone: 720.523.3278Email: [email protected]
www.solidfire.com
Questions?
