[CentOS-virt] Drupal/MySQL performance in Xen and OpenVZ

Wed Jun 8 16:31:33 UTC 2011
Eric Shubert <ejs at shubes.net>

On 06/08/2011 09:13 AM, Einar S. Idsø wrote:
> Hi Eric,
> On Wed, Jun 8, 2011 at 4:33 PM, Eric Shubert <ejs at shubes.net
> <mailto:ejs at shubes.net>> wrote:
>     Is your goal absolute best performance (why?), or simply adequate
>     performance?
> The hardware available to us is quite old, so pushing performance is
> absolutely the key issue. Stability/reliability and ease of maintenance
> are of course also factors. But since I've not have any bad experiences
> with OpenVZ in those respects, and I expect Xen to be at least as good,
> it pretty much comes down to performance.
>     I wouldn't expect to see Xen outperform OpenVZ. However, if your CPU has
>     has virtualization extensions, I would expect performance to be pretty
>     close between the two.
> Unfortunately it doesn't. We're doing a "parallell shift" from a host
> with 2xOpteron 250 (2.4GHz) to another host with 8xOpteron 880 (also
> 2.4GHz but dual-core), so apart from the increase in number of cores
> from 2 to 16 and amount of RAM from 6 to 32GB there's no real difference
> to be found. But since we're transitioning anyway, we're giving
> alternative technology a consideration.
> But okay, are you saying that Xen will at best be as good as OpenVZ
> using this hardware,

This is my expectation. I don't know of any reason why Xen would perform 
better than OpenVZ in this situation. Someone may know better than I do 
about this though. I would hope they'd chime in here if they do.

> and there's really not much point in me spending
> time learning Xen and running performance tests? That would save me
> quite a few workdays :)

I'd go this route, sticking with OpenVZ.
Unless you've nothing better to do. ;)

>     That being said, if you're considering Xen, I'd give strong
>     consideration to KVM as well.
> Thanks, I already looked at KVM, but it seems to require the
> virtualization bit, which means it is not an option for us.

If/when the time comes when you're migrating to hardware that supports 
virtualization, I'd give KVM strong consideration.

> Thanks for your input, Eric, it is much appreciated :)

Sure. Just don't hang me if/when I'm wrong. ;)

-Eric 'shubes'