This presentation, delivered by Howard Marks at Interop in Las Vegas May 2013 explores how system administrators can provide high performance storage for VDI implementations.

1. Storage for VDI
Or why storage vendors love VDI

2. VDI Looks Ready To Take Off
When will you deploy
VDI?
3 Months 3-6 Months
6-9 Months 9-12 Months
12+ Months
Have you started a VDI
pilot?
54%
46% Yes
No
Source: VIBriefing survey March 2012

3. But There’s a Disconnect
Reasons for VDI
43%
Better Endpoint Management
Lower cost
"Cloud"
Security
Reasons for VDI stall
31%
29%
22%
19%
Cost
Performance
Software Licensing
Storage Cost
Source: VIBriefing survey March 2012

4. Desktop Virtualization Expenses
4
Source: Gartner Dataquest
41%24%
8%
8%
1%

5. Everyone’s Talking VDI
• 76% are choosing VDI to:
– Save Costs
– Improve management
• 54% project total cost <$500
– One writer claimed <$200 VDI cost
• 80% Prefer persistent desktops for
knowledge workers
Virsto sponsored survey of 500 IT professionals 3/2012

6. The Sad Truth
• Most success stories are task workers
– Call centers, healthcare, Etc
• Much of your desktop support is user support
• Enterprise storage is expensive
• VDI creates high IOP density
• According to that same Virsto study, 46% of
the VDI projects are stalled
– Because of performance and/or cost

7. VDI and Storage
• Desktop disk:
– 30-40GB, 100 IOPS
– 200 desktops = 6TB, 20,000 IOPS
– 100+ 15K RPM drives RAID 10
• Windows 7 with AV 2x IOPS of WinXP
• VDI user steady state IOPS
– Light 6-12
– Power 5-40
• But you need to plan for peak

8. VDI Presents Unique Workloads
• Highly variable but coincident (boot/login in morning)
• Steady state 50+% write
200 Desktop VDI Storage Performance Demands

9. Anatomy of a Linked Clone
• Master Replica
– Common data
• Delta Disk
– Accumulates changes
from master per clone
• Disposable
– Swap, Temp Etc.
• Persistent (Opt)
– Additional drive letter
– Permanent data

10. Plus The Persona
• Roaming Profile
– Redirected USERSRacerX
– Copied to C: on login
– Issues:
• Long login/logout
• Disk space consumption
– Especially on shared systems
• More granular approaches like View Persona
Management better

11. About Desktop Persistence
• Non-Persistent desktops
– Delta disk discarded at shutdown/logout
– For task workers
• Persistent linked clones
– Preserve delta disk, persistent disk
– Allows centralized patching via re-composition
• Full clones
– Complete virtual PC

12. Living with Linked Clones
• Constant growth
– At VMware 1GB/user/week
– Can overwhelm initial savings
• IOP concentration on Master Replica
– Good use of a little flash
• Recomposing resets non-persona data
– Installed Applications
• Browser plugins, Etc.

13. Basic VDI Recommendations
• Use linked clones or deduped full clones
• Put master image on flash (many reads)
– More IOPS to Delta during steady state though
• Separate differencing data
– User profiles
– Swaps
• Try to avoid IOPS to spinning disk
– Use RAM or flash
• $/IOP not $/GB

14. View Storage Accelerator
• AKA Content Based Read Cache
• Up to 2GB RAM as a read cache
• Content Based means cache is deduped
• Most effective at boot
– Cause that’s when lots of common data reads

15. View Storage Accelerator vs. Boot
Storm

16. And vs. AV Scan Storm

17. Atlantis ILIO
• Dedupes data
• Accumulates writes to 64KB
• Larger read and write RAM Cache
• Can install on each host or Top of Rack

18. The Good News
• VDI Images are just desktops
– HA may be less important than performance
– I would use a single controller Flash system
• All the storage startups are validating VDI
solutions
• Local storage could be an answer
– Especially for non-persistent clones
– Consider local SSD, SSD caching RAID
controller

19. Things to look for in VDI Storage
• Substantial flash component
– 10% or more
– All flash for cast of thousands
• Good snapshots
– EG: Nimble, TinTri, NetApp
• VAAI Xcopy integration
• Data Deduplication
– Greenbytes, Pure, Astute for all flash
– TinTri, Tegile, Nexgen hybrids

20. Server Flash Caching Advantages
• Take advantage of lower latency
– Especially w/PCIe flash card/SSD
• Data written to back end array
– So not captive in failure scenario
• Works with any array
– Or DAS for that matter
• Allows focused use of flash
– Put your dollars just where needed
– Match SSD performance to application
• Politics: Server team not storage team solution

21. Server Side Caching State of The Art
• Proximal Data, Flashsoft (Sandisk) install in
hypervisor
– But are write through cache
• Speeds reads but passes writes through
• Most others are server only (agent based)
• Write back is coming
– Will write to SSD in n servers (n=2-3)
– Will require low latency net
– PernixData 1st more coming

22. Full Clones and Deduplication
• Full clones manage like desktops
– Good news if you manage desktops
• But most people don’t use Kace or LANdesk
• Full clones are fully persistent
• Deduplication reduces swap space too
– 100 new linked clones = 200GB swap reserve
• Flash eliminates read performance penalties
• Inline better than post process for live data

23. The Don’ts
• Don’t use RAID-5 spinning disks for VDI
– VDI workloads have lots of small writes
– RAID-5 amplifies 3-6:1
• Expect an all disk solution to serve >50 users
– Conventional wisdom = dedicated storage
• Expect $100/user costs
• Limit your options to established
vendors/products

24. Questions and Contact
• Contact info:
– Hmarks@deepstorage.net
– @DeepStoragenet on Twitter