In our tests of Vmware's Infrastructure 3 Suite, the performance overhead of VMware ESX Server, while typically less than 10 percent, spiked as high as 20 percent. We're not saying running VMware will hobble your systems--hardware virtualization simplifies server consolidation, saving money and data-center real estate while cutting power usage, and double-digit performance hits can be avoided with proper planning. But there is an undeniable cost in terms of performance.
In tests at our Boston partner labs, we found the primary benefit of running ESX Server is, not surprisingly, making the most of hardware resources by letting existing servers run more apps. In fact, virtualization may be server vendors' worst nightmare: Gartner sees a slim possibility that the technology could reduce the compound annual growth rate for x86 servers to--get this--negative 0.6 percent by 2010. We expect savings in data center power as well.
Oddly enough, then, when we recently asked readers which tech buzzword they most despise, virtualization came in a strong second, just behind SOA. One in four respondents threatened bodily harm to the next salesperson who mentioned it, and 20 percent said they didn't realize expected benefits.
Still, virtualization is here to stay, and that's a good thing despite its apparent image problem. Whether you use Microsoft Virtual Server, VMware, Xen or another package, virtualization delivers a raft of benefits, from better use of physical assets to improved management of applications to the ability to divvy up resources across machines in a way that the sum of a virtual assigned resource--such as memory--exceeds actual physical memory. Using virtual machines may reduce physical server count by moving older applications off older hardware to newer systems that are less likely to experience hardware failure or, in the event of failure, have better parts availability. We found ways to boost the payoff from virtualization technologies, and our testing highlights which areas will suffer least from performance drags.
Chip Changes Propel Virtualization