We recently completed a massive round of testing looking at many of the different deployment configurations we can do with a Windows 7 desktop in XenDesktop 7.7. We wanted to look at how different factors might impact single server scalability.

• PVS vs MCS
• PVS Disk Cache vs RAM Cache
• Citrix Policies: Very High Definition vs High Server Scalability vs Optimized for WAN
• Windows 7 optimizations

Each test was conducted utilizing the same, knowledge worker workload.

As you see, each test builds upon the previous test while only modifying a single parameter. As I’ve gone through the initial results, some things quickly popped out at me:

1. Machine Creation Services, from a purely single server scalability perspective, shows some impressive numbers.
2. Enabling the RAM Cache feature within Provisioning Services gave us a 9% gain in server density.
3. Every hypervisor tested showed similar percent changes between the different tests.
4. There was little difference between High Server Scalability and Optimized for WAN because the items within the policy were not a significant part of the tested workload.
5. Switching from the Citrix Very High Definition User Experience Policy to the Citrix High Server Scalability Policy improved server density by a whopping 30%.

Why did we see such a gain when moving to the High Server Scalability policy? Because the Very High Definition User Experience policy utilizes the H.264 codec, which gives the user a great experience, but at the cost of CPU utilization. When we switch to the High Server Scalability policy, we utilize the latest ThinWire technology. We are able to reduce CPU utilization while increasing server density by changing the way the system encodes the data.

In addition, these policies also modify how items are compressed, how many frames per second are transmitted, plus many more.

To learn more about the Citrix policies, check out the following blogs:

1. Why you should care about the new HDX ThinWire
2. HDX Policy Templates

Stay tuned for Windows 10 on XenDesktop 7.7

Server Specs:

• Processors: Dual Intel Xeon E5-2697 (12 cores each)
• Workload: Knowledge Worker
• VM Specs: 2vCPU, 4 GB RAM

Daniel (Follow @djfeller)
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