[CentOS] CentOS 5.6 and KVM failure

[Ian Forde]

On Thu, 2011-04-21 at 20:16 +0200, Kenni Lund wrote:
> 2011/4/21 Ian Forde <ianforde at gmail.com>:
> > Turns out that wasn't the only problem I faced in my migration.  With 2
> > KVM servers, both sharing a volume mounted via NFS for VMs, I migrated
> > all VMs to the second node, upgraded the first, them moved them all back
> > to KVM1.  Instant disk corruption on all VMs.  Boom.
> 
> Are you sure it was the migration and not the raw/qcow2 error which
> caused the disk corruption?

In the second pair of KVM servers, I'd made the changes to the xml files
and restarted libvirtd.  Then did migration of a VM.  Then watched the
corruption.  It's possible I may have needed to reboot the VM before
migrating, so that KVM absolutely knows what it is.  But nevertheless,
I'm now a little gunshy about live migration...

> I just had two Windows Servers with image corruption after upgrading
> from 5.5 to 5.6 and booting the first time with the raw setting,
> before changing it to qcow2 :-/
> 
> These two images were both on the same host, which is plain CentOS 5
> *BUT* with a 2.6.37 kernel (and therefore 2.6.37 KVM module) from
> elrepo...
> 
> It could be my special case of running with a vanilla KVM-module +
> CentOS KVM userspace which allows the corruption to happen, but if
> other people are seeing disk corruption with the regular
> kernel/kmod-kvm, then this "known issue" should probably have a big
> fat red warning in the release notes..

Yeah.  I completely agree.  I've got a steaming mess of VMs that I now
have to go and rebuild...

	-I