Join virtualization expert and industry veteran Ron Oglesby as he discusses local storage vs centralized storage models for VDI, including the arguments for and against local storage in VDI environments, a review of converged platform models (ie Nutanix) for VDI, and SSD tips and tricks
2. Agenda
Who cares about this session anyway?
Why is disk so important in VDI?
What are the key concepts to understand about VDI and
Storage
Then…
Why Local Storage rules for VDI
Why Local Storage Blows and You should ONLY use SAN
storage for VDI
3. Disk for Desktops? Who cares?
How many disks does it take to support 25 desktops?
4. Disk IO Understanding Limitations
Some References!
http://www.techrepublic.com/blog/datacenter/calc
ulate-iops-in-a-storage-array/2182
http://www.yellow-bricks.com/2009/12/23/iops/
5. Desktop IO Requirements?
Read:Write ratio can be as high as 50:50
60:40 to 70:30 is typical
Light Users = 4-5 IOps
Medium Users = 8-10 IOps
Heavy Users = 14-20 IOps
So if you have 50 medium users 400-500 Sustained IOps
So if you have 75 users/server? 750 IO? 4 disks before
RAID penalty?! 8-10 or more after penalty?
But what about boot / login storms?
6. Boot/Login Storms
At boot and login IO can be extreme
Even a medium user can generate 90-100 IO at login (why is
that 100 IO a ‘magic’ number?)
Boot storms can be even worse
The “good” thing about a boot storm is that it is
typically 90% Read!
No RAID penalty
Caching Helps
Still must be planned for.
7. Disk Costs and VDI
Dell 143 GB SAS 15K SAS Drive = $
Dell 100 GB SSD Drive =$$
EqualLogic SAS drives $$
EqualLogic SATA drives = $
EqualLogic SSD drives= $$$
Windows 7 “Thick Provisioned” 20-35GB
Windows 7 Linked-Clone = 8-10GB
9. Local Storage
Start with these questions:
How many of you boot your normal desktops from
the SAN?
How many of you boot your terminal servers from
the SAN?
How many of you have an extremely short SLA on
recovering your desktops?
11. Local Storage is about Perf vs Cost
Dell PCs can cost as little as $350!
Performance requirements require High end disk
Writable GB cost local vs SAN (SAS 15k)
RAID 1 143GB Drives $5/GB – SAN 15K $10-30/GB
Writable GB cost local vs SAN (SSD)
RAID 1 143GB Drives $5/GB – SAN SSD $30-70/GB
Why pay for centralized storage for a desktop?!
12. That’s ALL BS
SAN is the Solution to this
Problem
Local Storage is too limiting
14. All the features you love…
Do I really need to detail them all?
HA
DRS
FT
SRM
Storage vMotion
Etc
Etc
15. Spindle Count???
50 users per server at 20 IO each= 1000 Iops
100 users/server @ 10…
Boot / Login Storms?
RAID Penalty for writes?
DL 360’s have 6 drive bays. 15K drives at 180 IO each
1080 IOps before RAID penalty?
Are you a Blade shop?
Probably wont even get enough spindles in a server
16. “Cheap” SSD Issues
So you move to SSD instead of rotating disk…
$$$$ 149 GB SSD on Dell 610 $4,599.00
$$ 100 GB SSD on Dell 610 $1,949.00
Compare to 146GB at $359 on the same server.
Can you even get enough writable space on those
SSD?
Better to use SSD for just hot data rather than all data
17. Handle the IO with mixed disks
Leverage Hybrid Arrays
EqualLogic XVS
EMC FAST Systems
SSD / EFD can be used for HOT data
Smart systems will MOVE the data
Can also be used for writes!
18. What about that whole Dynamic Cloud?
Data Tiering
About placing data on the type of disk it NEEDS. Not fixed
provisioning
Moving data from slow, to fast to REALLY fast disks
Only moving small parts of data not whole VMDKs?!?!
Elasticity in the VM environment
Dynamic increases/decreases in capacity
Provisioning times increase – sometimes dramatically
Recovery and flexibility in the toilet
19. So what does Unidesk think?
We don’t care….
So what to we do?