20 Dell 1955 Blades; 16G ram; 70GB SAS 10K drive (one) on which ESX 3.0 is hosted (or a variety of Xen flavors); four gigabit ethernet controllers per blade; CISCO 4948 48 port switch, with 4 ethernets per blade bonded; CISCO 6504e core with Sup-32; Net App 3020 and 3050 for NFS and iSCSI; some EMC Clarion units, likewise.

For CPU we used SPEC CPU 2006 and score about 5-6ish % on VMWare as the same test done on those blades in hard metal. Xen is undiscernably different to the subjective eye than hard metal. I would have to break out large batch testing methodology and run the results through inferential statistics to conclude that there was a difference at all.

I/O is a different story.


The Xen performance claims and the VZ performance claims aren't really useful. They're theoretical. As in, "theoretically, we can stack 100 operating systems on this blade efficiently." Think about that. That's just plain nuts. I can't think of a real use case for that.

BTW, if you like OpenVZ, and have the right use case, the commercial Virtuozzo product ranks as the "best virtualization technology that no one has ever heard of" in my book. They really have their IT management story down pat.

C//