Resource pools w/ XenDesktop, is it worth it?

[khughes]

If it's been one thing I have never fully grasped it would be resource pools, so I'm asking the experts here.  We're getting ready to change from a XenApp server farm to a XenDesktop model.  As some of you know, our ESXi hosts have always been way under used but going from 4 XenApp servers where everyone shares those resources to 100+ XenDesktop virtual machines has me a little concerned on how it'll impact the cluster.

My biggest fear is that a desktop instance starts doing something extremely heavy and takes away needed resources from a production server.  A thought which entered would be to create a resource pool for the XenDesktop instances which would always take a backseat to the servers should a conflict come into play.  Right now the XenDesktop instance virtual machines are configured with 1 vCPU and 800MB of RAM.  They'll be sitting on a cluster of 5 hosts, three with two six-core processors and 64GB of ram, and the other two hosts have two eight-core processors and 64GB of ram.

In short, is it even worth it if there hasn't ever been any resource contention?  If I created a resource pool for these XenDesktop instances would it only go into effect if there was resource contention, if there was no contention they would operate as if there wasn't a resource pool in place?

Thanks for any input or recommendations for a VDI deployment.

[sparrowangelste]

you have 68 cores among your hosts

with 100+ machines coming in it might be good future proofing to use a resource pool with higher shares dedicated to your servers then your xen desktops

with expandable /unlimited reservations you should be able to work as if no pool was there if there is no contention.

[Bigi201110141]

The recommendation was always to keep the VDI and Servers workloads on sepearate Host Clusters. This way you would avoid any contention while keeping things as simple as possible.

[khughes]

While I'm sure that is the white paper "best practices" guide, they rarely apply to most cluster builds. If I had another $60-80k to drop on hardware and host licensing, I would go that route, but it looks like adding in a resource pool to keep servers and desktops separate would be a good idea.