[CentOS] XEN or KVM - performance/stability/security?

[Pasi Kärkkäinen]

On Mon, Apr 23, 2012 at 11:01:12PM +0300, Peter Peltonen wrote:
> Hi,
> 
> On Mon, Apr 23, 2012 at 10:54 PM, aurfalien <aurfalien at gmail.com> wrote:
> >
> > I also prefer KVM over Xen, mainly I don;t have to do anything special when maintaining the env.
> >
> > But I haven't notice an improvement over Xen.
> >
> > I really like the fact that the guest OS has a stock kernel, etc..
> 
> I do not quite see how Xen requires one to do something special for
> maintenance? With pygrub you can use the stock kernel with your Xen
> domUs just fine. I have not seen any issues with stability either, but
> then again I am running mostly just web and mail servers without
> really high traffic.
> 
> But if KVM would offer improvements for performance over Xen, I should
> perhaps try it out, as sometimes when doing backups and other things
> that require a lot of disk I/O a better performance could be wished
> for...
> 

Disk performance is usually mainly limited by the number of physical disk spindles,
and the raid level, and not so much about virtualization.

Anyway some Xen PV vs. Xen PVHVM vs. KVM benchmarks from XenSummit 2011:
http://xen.org/files/xensummit_santaclara11/aug3/6_StefanoS_PVHVM.pdf

-- Pasi