Jeroen van de Kamp
Ruben and I are pleased to announce we finally can release the long awaited Phase III whitepaper. As promised: this one does a true VDI deep dive. We think we have interesting new content, and more importantly, many new insights.
More and more organizations are planning a move to VDI. Experience in many VDI projects has proven so far that the performance and sizing issues are still a major hurdle to overcome. Often, VDI results are disappointing because the VDI environment is not properly sized and tuned. In practice, storage remains the number one challenge in today’s VDI deployments.
In this whitepaper Windows XP and Windows 7 are extensively compared. Specifically, the I/O behavior of Windows XP and Windows 7 is investigated in detail. By evaluating the different phases of a desktop workload, completely new insights are given.
Windows 7 has a much bigger disk footprint and consumes more memory than Windows XP. It would be reasonable to expect that Windows 7 requires more resources than Windows XP. Although this is certainly true, several tests in this whitepaper prove that Microsoft managed to optimize Windows 7 disk I/O behavior in specific phases of a desktop workload in comparison to Windows XP.
Many best practices are available to optimize Windows 7. Project VRC performed tests with the default optimizations configured by VSI (referred in this document as ‘VSI optimizations’) and additional optimization best practices that are specific to Windows 7 (referred as ‘VRC optimizations’). Both from an I/O and VSImax (maximum capacity) perspective, these ‘VRC optimizations’ proved to have a significant positive impact.
Project VRC also investigated the performance impact of topics like ‘Page file configuration’, ‘Address Space Layout Randomization’, ‘VM logging’, ‘ESXTOP’, ‘1 vs 2 vCPU’s’, ‘ESX 4.0u2 vs ESX 4.1’, and ‘Overcommitting Memory’. There are many lessons to be learned here, but the impact of disabling ASLR was striking. It is difficult to blindly recommend disabling such an important security feature, but the impact is large enough to consider it.
All tests were performed with either vSphere 4.0 U2 or 4.1 as the hypervisor and all VDI tests were performed using View 4.0. Apart from specific recommendations for vSphere, all Windows related conclusions are valid for any kind of hypervisor or VDI solution.
The ‘Project VRC phase II version 2.0’ whitepaper evaluated the impact of configuring a higher HaltingIdleMsecPenalty value on vSphere with Terminal Server workloads. This setting improved hyper-threading performance considerably for vSphere under high loads. Although no specific hints were given by VMware or the community, Project VRC investigated if a higher HaltingIdleMsecPenalty value would benefit VDI workloads. Surprisingly, a significant performance increase (more than 20%!!!) was witnessed for both Windows 7 and Windows XP workloads. The difference was so high that Project VRC internally started to call this the ‘Red Bull setting’.
Project VRC highly recommends to evaluate the data in this document carefully. Project VRC realizes there are always valid reasons not to use a specific settings mentioned in this paper. Real world VDI environments will always be different from the test-setup in the Project VRC labs. More importantly, Project VRC must emphasize that it is crucial to test and validate these optimizations in your own VDI deployment.
As usual, you may download the paper from www.virtualrealitycheck.net.
Follow Ruben on twtter: @rspruijt
Follow Jeroen on twitter: @theJeroen
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