Working at ibcn.intec.ugent.be, I am conducting some performance tests on different platforms (Xen, KVM, VMWare) and also on different host OS systems (Debian, Ubuntu, CentOS) and can acknowledge this. While those tests aren't finishedn and no report was written yet (I plan to do this in the following month, an dhoperfully publish it somewehere) I can give some conclusions.
On 12 May 2010 08:30, David Peall <[email protected]> wrote: > Thats a big pill to swallow for KVM. > > Any ideas what is the best way to get disk performance using KVM. > "Don't use local disks." KVM performs badly (ATM), I fail to see a solution right now. I wouldn't recommend using virtualisation when you need strong disk performance, like for databases. If you really must use virtualisation, *and* need the best performance, consider runnig Xen on Debian Lenny, or VMWare ESX(i) 4 Some conclusions to my tests. - Processor wise they all perform well- Memory bandwitch is overall comparable, but best on vmware - network speed is varying, but no conclusive tests so far; tuning for gigabit connections is of course needed - disk access is the major botle neck on *all"platforms About disk access I can add also those first observations: - vmware performs best, closely followed by Xen (using paravirtualisation of course) - KVM (using virtio) performs worse and still has a lot to catch up on Xen - a recent KVM/Ubuntu combo (Karmic, Lucid) is performing worse than Centos 5.4 /KVM (which carries older but patched versions of KVM and vmlinuz) - Debian Lenny + Xen is far more performant Overall, I get a strong feeling that the Ubuntu flavours I tested perform badly, even compared to older versions of other platforms. It seems very obvious that Red Hat patches to the kernel are very optimized. It might be interesting to consult the kernel team, but right now, I don't have the numbers compiled and ready to be published. I'll ping the list when that is ready. -- Met cordiale groet, Serge van Ginderachter
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