As most of you know, the VMware ESX EULA explicitly prohibits publishing of performance test results without its approval:
"You may use the Software to conduct internal performance testing and benchmarking studies, the results of which you (and not unauthorized third parties) may publish or publicly disseminate; provided that VMware has reviewed and approved of the methodology, assumptions and other parameters of the study."
However, the brave Virtualization Review team published a performance comparison of the three hypervisors and came to the following conclusions:
- VMware ESX is optimized for a large number of less-intensive workload virtual machines.
- For intensive workloads Microsoft Hyper-V and Citrix XenServer should be considered-even if this means adding another hypervisor into the data center.
The reality is that all three hypervisors are enterprise-grade and the performance differences of choosing one versus another are negligible. The following factors are more critical in selecting a hypervisor than performance factors alone:
- Cost-performance Ratio: all other things being equal, the cost is a key factor in selecting a virtualization platform. For example, in a recent Citrix XenServer vs. VMware Infrastructure price comparison, it is evident that Citrix is a much more cost effective alternative (as long as HA and DRS are not must-have).
- Management Applications: without management applications, the value of a hypervisor is marginal, regardless of its performance. VMware offers the richest set of management applications by a significant margin. Citrix offers a number of management applications such as LabManager and StageManager through partners such as VMLogix.
- Enterprise Features: VMware currently leads the way in offering enterprise features such as VMotion, Dynamic Resource Scheduler (DRS) and High Availability (HA). Citrix also offers HA for Citrix XenServer through Marathon Technologies and XenMotion. Microsoft is planning to release live migration in Windows Server 2008 R2.
Regardless of which virtualization platform is chosen, proper capacity planning and virtual infrastructure design are vital for avoiding under- and over-provisioning of target systems. Products such as Lanamark Suite make it possible to efficiently analyze existing physical infrastructure and design virtual infrastructure that optimizes performance and maximizes return on investment regardless of virtualization platform selected.