[Linux-cluster] Xen on RHEL cluster

[Pasi Kärkkäinen]

On Mon, Mar 01, 2010 at 12:26:15AM +0100, Jakov Sosic wrote:
> On 02/26/2010 06:29 PM, Jakov Sosic wrote:
> > Hi.
> > 
> > I'm using Xen on RHEL cluster, and I have strange problems. I gave raw
> > volumes from storage to Xen virtual machines. With windows, I have a
> > problem that nodes don't see the volume as same one.... for example:
> > 
> > clusternode1# clusvcadm -d vm:winxp
> > clusternode1# dd if=/dev/mapper/winxp of=/node1winxp
> > clusternode2# dd if=/dev/mapper/winxp of=/node2winxp
> > clusternode3# dd if=/dev/mapper/winxp of=/node3winxp
> > 
> > When I download these files and diff them, they all three differ.
> > 
> > Also, sometimes very strange things happen. For example I download some
> > file into winxp, shut it down, then start it on another node, and file
> > is missing?!?!?!?!
> > 
> > Should I use CLVM and not raw volumes from storage? Why is this happening?
> 
> It seems that CLVM is solution (migrated whole cluster to clvm today),
> and that the bug is double caching (both domU and dom0 caching), and
> that bugs like this occur when using raw LUNs:
> https://bugzilla.redhat.com/show_bug.cgi?id=466681
> 

Oh yeah, this bug can definitely affect you if you're accessing the same 
disk images from both domU and from dom0.

-- Pasi