There’s been so many discussions on whether to virtualize Citrix Servers or not I can hardly keep track. But today I was pointed out to a discussion on the VMTN forum. Especially Jason Boche’s contribution to this thread is very valuable and makes sense on why you actually should virtualize your Citrix environment. Jason discovered the following:
A few of the things we’re seeing:
1. The VM is handling slighly more users with a fraction of the hardware used
2. The VM is managing application memory more efficiently which I think will allow us to get more theoretical users on a VM than on physical hardware because with 4GB of usable RAM, we always run out of memory first. I need to find out if the memory efficiency is is due to VMware’s Content-Based Page Sharing (see http://www.waldspurger.org/carl/papers/esx-mem-osdi02.pdf). My knowledge of VMware’s page sharing thus far was that pages were shared between VMs only. The memory efficiency I’m seeing when running Citrix inside a VM suggests that VMware page sharing is being used to share common memory pages inside of just a single VM of the same Citrix published application that is being run 40 times in 40 concurrent users sessions.
This is also something that’s new to me, VMware is also doing intra-VM page sharing besides inter-VM page sharing. Which indeed can be really beneficial for Server Based Computing. In the end this will enable you to virtualize more servers on the same hardware and taking advantage of those quadcore processors like no other platform does. Especially the dual-quadcore servers nowadays hardly ever get fully utilized with additional memory and VMware you can solve this inefficient usage of hardware.
Not only the usage will be more efficient but the uptime and portability will increase and with the usage of templates and for instance Thinstall it should be very easy to prep new Citrix servers in a matter of minutes. Than again with Windows Server 2008 and Thinstall small to medium companies might not even need Citrix, and I’m not even talking about the new upcoming VDI features like offline working, patch one patch many and linked cloning.
SBC and VDI will definitely make a giant leap over the next months!