One of the benefits of Personal vDisk technology is the ability to capture the storage savings of thin-provisioned pooled desktops while maintaining a persistent, flexible desktop that survives reboots, and even base OS patching.
So how much storage savings can you get?
Let’s look at the following scenario:
A desktop admin wants to create 1000 desktops for their knowledge workers. They know a locked-down desktop experience won’t fly with their users so they assume they need dedicated desktops. Some back of the envelope calculations might look like this:
- 30GB for OS, Base Apps, and Service Packs
- 4 GB for Swap and Temp files
- 10GB for other user “stuff” (files/apps)
At first blush, you might plan for ~45GB per user, but you could then apply a deduplication benefit (~50%) from your SAN vendor. Storage deduplication is completely independent of the virtualization technology in this case.
So with a dedicated desktop model for 1000 desktops with Storage Deduplication in the SAN, you could need around 22TB of storage capacity sized for 10-15 IOPS per desktop.
Alternatively, in the personal virtual desktop model using a Personal vDisk, The 1000 desktops might be sharing 1-2 30GB base images, and then each user would then be provisioned a 10GB Personal vDisk. The admin may choose to cap the size of that Personal vDisk and leverage folder redirection to keep user data on an appropriate storage target (filer with backup, etc.).
In this case, using PvD with XenDesktop leveraging thin-provisioned desktops the total storage requirement would be around 7.5TB, or a savings of 65%. However, if leveraging XenServer with IntelliCache, many of the reads and non-persistent writes can be cached on the host bringing the storage requirement down to under 5TB, a total savings of more than 78% over dedicated desktops.