Among the licensing kerfuffle surrounding vSphere 5.0, VDI users may have overlooked some interesting information that VMware posted about VDI and vSphere 5.0 today. Myself and other bloggers like Brian Madden have done some analysis on what vSphere 5.0 means for VDI, mostly for non-VMware products such as XenDesktop.
However, VMware’s blog post from today contains some very interesting information that I had not seen before. But before we get to that, let me quickly recap the two primary options for VDI on vSphere 5.0. (For more details see my blog post here.)
First, you can buy/use regular vSphere licenses and work within the vRAM entitlement limits. Depending on the number and size of VDI VMs, this may or may not be the best deal. Second, and new to vSphere 5.0 is the vSphere Desktop license which is sold in packs of 100 VMs for $6500. This removes the vRAM entitlement limit, but imposes other limits such as not running server OS VMs on the same hosts as VDI VMs. But overall, this is a better ROI as the per-VM costs are generally lower.
Now here’s the new information that I just learned about. According to a VMware FAQ in the blog today “Customers who purchased licenses for vSphere 4.x (or previous versions) prior to September 30, 2011 to host desktop virtualization, and hold current SnS agreements, may upgrade to vSphere 5.0 while retaining access to unlimited vRAM entitlement.”
Whoa…stop the train! Did I read that right? You can “violate” the vRAM limitations if you purchase vSphere 4.x licenses before Sept 30, 2011 for VDI? Yes, but what’s the catch? Well there are a couple, but they aren’t unreasonable. VMware states you must use a separate vCenter instance that is dedicated to VDI in order to re-purpose your vSphere 4.0 licenses for VDI and remove the vRAM caps. VMware states this is required, not optional. You also can NOT run general purpose (non-VDI) server VMs on the same hosts, but you could run VDI broker/monitoring VMs on the same hosts.
Now all the bloggers that did elaborate calculations for VDI can toss much of that work to the wind, recommend people deploy a dedicated vCenter server to manage VDI-only hosts, and be done with it. Companies just getting into VDI probably should go the vSphere Desktop SKU route, but it’s nice to know existing VDI customers aren’t left in the cold. You could need to pony up for an additional vCenter license, depending on your existing topology.
With XenDesktop in mind, this also makes some sense. Why? Who knows when Citrix will officially support vSphere 5.0 for XenDesktop. I would guess it will be several months after vSphere 5.0 code hits the streets. So you can dedicate a vCenter 4.x instance to XenDesktop, then migrate your other production servers to vSphere 5.0 on your schedule without worrying about XenDesktop impacts.
Along with the new entitlement increases announced today, I think the grandfathering of VDI only hosts into a vRAM entitlement free environment is a great gesture on VMware’s part. Thank you!
P.S. It’s not entirely clear to me if one leverages the vSphere Desktop licenses whether that also requires a separate vCenter instance or not. I suspect it does, unless there’s a way to tell vCenter a host is only for VDI usage.