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

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@shubes.net mailto:ejs@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. ;)