Citrix hase realese another interesting document about Desktop Virtualization based on XenDesktop 4.0.

This, titled High Availability for Desktop Virtualization – Reference Architecture, is an architectural blueprint to build an end-to-end environment that is fault tolerant at several levels: at the virtual desktop hosting platform (aka the hypervisor) one, at the guest operating system delivery one and at the application/user environment delivery one.

The architecture involves the use of technologies like NetScaler, XenDesktop Roaming Users and XenServer Pools and XenMotion.

Notice that Citrix also released a companion paper titled High Availability for Desktop Virtualization – Implementation Guide, which is a step-by-step walkthrough of the configuration described in the previous paper.