[CentOS] Virtualization platform choice

Nico Kadel-Garcia nkadel at gmail.com
Sun Mar 27 13:54:52 UTC 2011

On Sun, Mar 27, 2011 at 9:41 AM, Steve Thompson <smt at vgersoft.com> wrote:
> On Sun, 27 Mar 2011, Jussi Hirvi wrote:
>> KVM would be a natural way to go, I suppose, only it is too bad CentOS 6
>> will not be out in time for me - I guess KVM would be more mature in
>> CentOS 6.
> I have been using Xen with much success for several years, now with two
> CentOS 5.5 x86_64 Dom0's, hosting 29 (mixed Linux and Windows) and 30 (all
> Windows) guests respectively, using only packages from the distro along
> with the GPLPV drivers on the Windows guests (so it's Xen 3.1, not the
> latest). A couple of weeks ago I decided (on the first of these hosts) to
> give KVM a look, since I was able to take the machine down for a while.
> All guests use LVM volumes, and were unchanged between Xen and KVM (modulo
> pv drivers). The host is a Dell PE2900 with 24 GB memory and E5345
> processors (8 cores). Bridged mode networking. What follows is obviously
> specific to my environment, so YMMV.
> The short story is that I plan to keep using KVM. It has been absolutely
> solid and without any issues whatsoever, and performance is significantly
> better than Xen in all areas that I have measured (and also in the "feels
> good" benchmark). Migration from Xen to KVM was almost trivially simple.
> The slightly longer story...
> First. With Xen I was never able to start more than 30 guests at one time
> with any success; the 31st guest always failed to boot or crashed during
> booting, no matter which guest I chose as the 31st. With KVM I chose to
> add more guests to see if it could be done, with the result that I now
> have 36 guests running simultaneously.
> Second. I was never able to keep a Windows 7 guest running under Xen for
> more than a few days at a time without a BSOD. I haven't seen a single
> crash under KVM.
> Third. I was never able to successfully complete a PXE-based installation
> under Xen. No problems with KVM.

How did you get the PXE working? I had real problems. Mind you, that
was RHEL 5.4 and CentOS 5.4 for the server host, so it may have

And do you have widgets for setting up the necessary bridged
networking? I left mine behind at a consulting gig, and haven't asked
for copies of them.

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