One question that the RDS team is asked is whether running Terminal Server virtualized is supported and recommended. To answer this question we’ve recently conducted some performance testing of this configuration using WS08 Terminal Server running as a guest on Windows Server 2008 R2 Hyper-V. To answer the first part: this is a supported scenario.
The second question is what recommendations would we make for any customer planning to run Terminal Server 2008 virtualized. To answer this question, we conducted performance testing using our internal knowledge worker simulation which mimics users logging on to their desktop, conducting tasks using the Office productivity suite as well as other applications, and logging off. We conducted our testing using both non-SLAT and SLAT hardware and found that SLAT enabled processors increased the number of sessions by a factor of 1.6x to 2.5x compared to non-SLAT processors.
Given that the Terminal Server workload is highly variable as far as scaling based on the usage scenario of the users, we recommend that customers test virtualized Terminal Server with their specific client usage and utilize SLAT enabled processors given the scale improvement that SLAT provides the Terminal Server workload.
We do plan on posting a performance / scale white paper for Windows Server 2008 R2 in the coming months that will include more detail.