There are many opinions in the air about the impact that virtualization has on performance, so I thought a short blog would be good to explain (as best I can) virtual machine performance characteristics with pointers to relevant benchmarks and technical papers.

My background is that I was an early Product Manager working on VMware ESX Server (from version 1.5) and among other things ran product management for VMware for a few years. As a product management guy, I kept track of the output of the engineering performance group, and as a result had a reasonable high level (although never code level) understanding of the whys and wherefores of virtualization performance. Although I’m not as fresh on virtualization as I once was, I’ll try to do my best here. I also want to thank Steve Herrod at VMware, and Simon Crosby at Citrix for providing a technical sanity check on the blog contents, although I retain responsibility for any mistakes and oversights.