The true cost of virtual server solutions

By the Taneja Group

-- VMware recently contacted the Taneja Group to conduct an assessment of how VMware ESXi 3.5 and Microsoft Hyper-V compare when it comes to consolidating multiple servers – what we refer to in our Technology Validation Report as "VM density." The  Taneja Group executed a set of tests to evaluate hypervisor performance under different types of workloads.

Why is this important? Because it has a considerable impact on virtual infrastructure acquisition costs. A higher VM density translates into a lower number of physical servers required to support the virtual infrastructure. A higher VM density also leads to reduced guest OS licensing costs, which tend to be dependent on the number of hypervisor instances in an installation. Finally, a higher VM density can also reduce the cost of management servers and licensing, which with some solutions can be complex and expensive. Together, these costs outweigh any individual component or hypervisor costs, and paint a picture of total cost of acquisition.

Our hands-on validation revealed that VMware ESXi 3.5 can achieve a significantly higher VM density than Hyper-V, allowing users to consolidate more servers on a VMware platform. While VMware's advantage may not be surprising, the magnitude of the difference is striking: VMware ESXi 3.5 demonstrated at least a 50% (1.5 to 1) density advantage over Hyper-V across a variety of application workloads, and in some cases achieved a 100% (2 to 1) advantage. Thus, for a given application workload, if users can consolidate eight servers on Hyper-V, they will be able to consolidate 12 to 16 servers on VMware ESXi.

The rush of hypervisors into the marketplace, and the predominance of free hypervisors, does not mean that hypervisors are becoming commoditized. There are distinct differences between hypervisors, and VMware's time in the market has led to a level of maturity that pays off in performance and efficiency with hardware.

Based on our testing of VM density, and contrary to competitive claims and some prevailing end-user perceptions, the total solution cost of a VMware Infrastructure 3 environment is not significantly higher than that of a Microsoft virtualization environment, which consists of Hyper-V and Microsoft System Center. Given the VM density advantages of ESXi 3.5 demonstrated in this study, we found the cost per application to be 5% to 29% less expensive in a VMware Infrastructure 3 environment than in a Microsoft environment consisting of Hyper-V plus System Center.

In an economic environment that is mandating that users "do more with less," the efficiency of hypervisors is an often-overlooked aspect of virtual infrastructure acquisition that has a significant impact on total price. Organizations undertaking a server virtualization initiative can review our VM density findings in our report. Then use our findings, or your own evaluation, along with the associated cost-per-application assessment approach we review in the report, to identify the true cost of virtualization solutions you are considering. Viewing virtualization solutions through this lens will help you figure out how to do more with less.

The full report is available on the VMware and Taneja Group websites.

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This article was originally published on March 26, 2009