AP08 Virtualizing Citrix XenApp Application Server

One of the workloads which are not always succesfully deployed as virtual machines are Terminal Server/XenApp workloads. A Terminal Server consumes quite a lot more CPU cycles and does more context switches than the average workload. Lots of VMware customers decide not to virtualize terminal server.

The description of this session looked promising. The agenda listed an overview of best practises. Two staff members of VMware gave the presentation. Unfortunately the presentation  hardly gave any best practises. Since ESX 3.5 terminal server worksloads run much better as virtual machines. Best practises  described in communities and websites mostly are valid for ESX 3.0 or earlier versions. The presenters told their audience they do not want to publish best practises because  it is only valid for a certain version of ESX or even an update of ESX. Update 3 of ESX Server 3.5 can have a different best practise than Update 2! Customers have been blaiming VMware for not given right advise while using the best practise published by VMware.

Just a few advises were given:

-use an application set having applications used in  your organization for proof of concept of virtualized terminal servers. Benchmarks published on the internet often use a standard set of applications (like Microsoft Office). Results may differ from your own application set! 

-use 2 vCPU’s. This can deliver a much better performance than using one vCPU.

-if you are not satisfied with the performance, contact VMware. They are willing to assist you.

Overall I found this a disappointing presentation. Much more information on virtualizing terminal server and benchmarks can be found on the website  ProjectVRC (Vitual Reality Check) . This is a joint operation of Login Consultants and PQR. See http://www.projectvrc.nl/

Another interesting article on virtualizing XenApp is here http://virtualfuture.info/2009/03/citrix-xenapp-on-vmware-esx-1-or-2-vcpu/