The document presents an overview of Storage I/O Control (SIOC) by VMware, detailing its concepts, configuration, and best practices for managing diverse storage architectures. It emphasizes SIOC's role in enabling performance isolation among virtual machines through automatic detection of I/O congestion and demonstrates configuration steps for optimal usage. The roadmap and improvements in VMware vSphere versions 5.1 and 5.5 are also outlined, highlighting features that enhance storage management capabilities.

1. Storage IO Control: Concepts, Configuration and Best
Practices to Tame Different Storage Architectures
Sachin Manpathak, VMware
Mustafa Uysal, VMware
Sunil Muralidhar, VMware
VSVC5364
#VSVC5364

2. 2
Disclaimer
 This session may contain product features that are
currently under development.
 This session/overview of the new technology represents
no commitment from VMware to deliver these features in
any generally available product.
 Features are subject to change, and must not be included in
contracts, purchase orders, or sales agreements of any kind.
 Technical feasibility and market demand will affect final delivery.
 Pricing and packaging for any new technologies or features
discussed or presented have not been determined.

3. 3
VMware Vision: Software Defined Storage
Software Defined Storage
Software-Defined Storage Vision
Enable new storage tiers
Enable DAS & server flash for shared
storage along with enterprise SAN/NAS
Enable tight integration with storage
ecosystem
Tighter integrations with broad storage
ecosystem through APIs
Deliver policy-based automated storage
management
Automatically enforce per-VM SLAs for all
apps across different types of storage
“Gold”
Array(s)
“Silver”
Array(s)
Distributed
Storage
Hard
disks
SSD Hard
disks
SSD
Availability = 99.99%
DR RTO = 1
“Gold” SLA
Availability = 99%
Throughput = 1000 R/s, 20 W/s
Latency = 95% under 5 ms
DR RPO = 1’, RTO = 10’
Back up = hourly
Capacity res = 100%
Web Server
Database Server
Availability =
99.99%
DR RTO = 1 hour
Max Laten
“Bronze” SLA
Availability = 99%
Throughput = 100 R/s,10 W/s
Latency = 90% under 10 ms
DR RPO = 60’, RTO = 360’
Back up = weekly
Security = encryption
ReduceStorageCostandComplexity
App Server
Roadmap

4. 4
Software-Defined Storage: Summary Roadmap
vSphere storage
features
Storage IO Control,
Storage vMotion,
Storage DRS,
Profile Driven Storage
Enable New
Storage Tiers
Policy-based storage
management
Virtual Volumes
VM-aware data
management with
enterprise storage
arrays
Tight integration with
storage systems
Policy-based storage
management
For local storage
vSphere Storage
Appliance
Low cost, simple shared
storage for small
deployments
Virtual SAN
Policy-driven storage for
cloud-scale deployments
Virtual Flash
Virtual SAN
Data services
Virtual Flash
Write-back caching
Policy-based storage
management
For external storage
H2 2013 / H1 2014 RoadmapToday
Roadmap

5. 5
Outline
 Storage IO Control (SIOC) Overview
 Deployment Scenarios
 Improvements in vSphere 5.1 and 5.5
 Preview from SIOC Labs
Survey: http://bit.ly/siocsdrs

6. 6
The Problem
What you see
Database
Server Farms
Online store:
Product Catalog
Online Store:
Data Mining
(low priority)
Shared
Datastore
Online Store:
Order Processing
What you want to see
Shared
Datastore
Online store:
Product Catalog
Online Store:
Data Mining
(low priority)
Online Store:
Order Processing

7. 7
Solution: Storage IO Control
 Detect Congestion
• SIOC monitors average IO latency for a datastore
• Latency above a threshold indicates congestion
 SIOC throttles IOs once congestion is detected
• Control IOs issued per host
• Based on VMs and their shares on each host
• Throttling adjusted dynamically based on workload
• Idleness
• Bursty behavior

8. 8
Congestion Threshold
 Performance suffers if datastore
is overloaded
 Congestion threshold value (ms):
• Higher is better for overall throughput
• Lower is better for stronger isolation
 SIOC default setting: 90% of peak
IOPs capacity
 Changing default threshold:
 Percentage or absolute value
Throughput(IOPS)
Datastore Load
No benefit
beyond certain
load
Latency
Datastore Load

9. 9
Distributed Storage Access
10
10
10
50
20
30
50
1005030
Shares
vol1 vol1 vol1
 VMs running on multiple hosts
 Shared storage: SAN/NFS
 VMs interfere with each other
 No centralized control
 VM shares control amount of
IO throttling

10. 10
Control IOs Issued per Host (Based on Shares)
With SIOC: All VMs get equal queue slots
Without SIOC: VM C gets equal queue slots as VMs A+ B
VM Disk
Shares
A 1000
B 1000
C 1000

11. 11
What Do I/O Shares Mean?
 Two main units exist in industry
• Bandwidth (MB/s)
• Throughput (IOPS)
 Both have problems
• Using bandwidth may hurt workloads with large IO sizes
• Using IOPS may hurt VMs with sequential IOs
 SIOC: carves out storage array queue among VMs
• VMs reuse queue slots faster or slower (depending on array latency)
• Sequential streams get higher IOPS even if shares identical
• Workloads with high read cache hit rates
• This is a good thing!
• Maintains high overall throughput

12. 12
Configuring Storage IO Control
2 simple steps:
1. Enable Storage I/O Control on a datastore
2. Set virtual disk controls for VMs

13. 13
Enabling Storage IO Control

14. 14
Storage IO Control Configuration

15. 15
Setting Virtual Disk Shares

16. 16
Storage IO Control In Action
 New Datastore performance metrics
• Storage IO Control Normalized Latency
• Storage IO Control Aggregate IOPs
 Latency is normalized by I/O size
 Averaged across all ESX hosts
 SIOC invoked every 4 seconds
• Latency computation
• I/O throttling
40ms
30ms
20ms

17. 17
Outline
 Storage IO Control (SIOC) Overview
 Deployment Scenarios
 Improvements in vSphere 5.1 and 5.5
 Preview from SIOC Labs

18. 18
Deployment: Shared Storage Pools
 Enable SIOC on all datastores
 Use same congestion threshold
 SIOC will adjust queue depth for
all datastores based on demand
SIOC SIOC
BA
Shared Storage Pool
IO Queue

19. 19
Deployment: Auto-tiered LUN
 Set lower congestion threshold
• Based on LUN configuration
• Based on application needs
• More SSDs -> lower value
 SIOC will adjust queue depth
and do prioritized scheduling
Capacity Tier
Fast Tier
Medium Tier
One IO queue
SIOCSIOCSIOC

20. 20
VMs with Multiple VMDKs
 VM IO allocation on a datastore
• Sum of shares of all VMDKs
 A low priority VM with many
VMDKs may get higher priority
• Unusued shares flow across VMDKs
 VMDKs split across datastores
• No flow of unused shares
 Consider IO sum of shares per
datastore while provisioning
VMs.
800300 200200
500 200 800Allocations

21. 21
Best Practices
 Avoid mixing vSphere LUNs and non-vSphere LUNs on the same
physical storage
• SIOC will detect this and raise an alarm
 Configure host IO queue size with highest allowed value
• Maximum flexibility for SIOC throttling
 Keep congestion threshold conservative
• Will improve overall utilization
• Set lower if latency is more important than throughput

22. 22
VM Snapshots and Storage vMotion IOs
 VM snapshot and Storage vMotion IO charged to VM
 SIOC throttles all IOs from a VM
• IOs from Storage vMotion activity does not affect important VMs
• Storage array is not overwhelmed with IO activity burst
 SIOC’s distributed IO allocation consistent with ESXi host scheduler
• ESXi host scheduler does not differentiate Storage vMotion IOs

23. 23
NFS Only: Shared File Permissions
 SIOC uses shared files for its distributed computation.
• Needed to compute entitled host queue size across hosts
 Likely causes
• Improper implementation of NFS storage in vSphere: no root squash
 Best practices
• Always use recommended security setting on NFS datastores

24. 24
Outline
 Storage IO Control (SIOC) Overview
 Deployment Scenarios
 Improvements in vSphere 5.1 and 5.5
 Preview from SIOC Labs

25. 25
Improvements in 5.1 and 5.5 releases
 Automatic congestion threshold
• Can use % of peak capacity to determine congestion threshold
 Lesser disk IO
• Reduction in SIOC IOs when LUN is idle
 Improved stats reporting
• SIOC based storage statistics available by default in vSphere 5.5
 Full interop with storage workflows and conditions in vSphere 5.5
• Unmount, Destroy, APD (all paths down) and PDL (permanent data loss)
• Fixed in 5.1: “Unable to delete datastore with SIOC enabled”

26. 26
Using SIOC with Virtual Flash (vFlash)
 SIOC and vFlash are
complementary
 SIOC does not throttle SSD
reads/writes
 SIOC proportionally allocates
post-cache IOs
• Latency controls during warm-up
 Best Practice: Allocate shares
to VMs consistent with vFlash
allocation
vFlash Infrastructure
Cache software Cache software
I/O Queue
Storage

27. 27
Outline
 Storage IO Control (SIOC) Overview
 Deployment Scenarios
 Improvements in vSphere 5.1 and 5.5
 Preview from SIOC Labs

28. 28
IO Reservations
 IO reservation control
• In addition to shares and Limits
• Specified per VMDK in IOPs
 SIOC distributes capacity using
shares, limits and reservations
 Storage DRS considers IO
reservation during initial
placement and load balancing SIOC SIOC
R=100,200 IOPs R=150 R=250
Estimated
Peak: 5430
IOPs

29. 29
Resource Controls
 Fine-grain resource controls
• Per VM latency along with R,L,S
• Latency managed by Storage DRS/SIOC
• Enforced by smart arrays (vVols/vSAN)
 IO Resource pools for VMs / VMDKs
• Reservation, Limit, Shares control for a group of VMs or VMDKs
• No need to set per VM controls

30. 30
Summary
 Easy to use – just two steps
• Enable Storage IO Control on a datastore
• Set IO shares and limit values for virtual disks
 Performance isolation among VMs using IO shares
 Automatic detection of I/O congestion
 Protect critical applications during I/O congestion

31. THANK YOU
http://bit.ly/siocsdrs

33. Storage IO Control: Concepts, Configuration and Best
Practices to Tame Different Storage Architectures
Sachin Manpathak, VMware
VSVC5364
#VSVC5364

34. 34
Thanks!
Sachin Manpathak (smanpathak@vmware.com)
Mustafa Uysal (muysal@vmware.com)
Sunil Muralidhar (muralidhars@vmware.com)
http://bit.ly/siocsdrs