[ClusterLabs] Antw: VirtualDomain as resources and OCFS2

Lentes, Bernd bernd.lentes at helmholtz-muenchen.de
Tue Sep 11 09:21:06 EDT 2018

----- On Sep 11, 2018, at 8:54 AM, Ulrich Windl Ulrich.Windl at rz.uni-regensburg.de wrote:

> Hi Bernd,
> the disappointing answer ist this: With cLVM you cannot make snapshots of the
> LVs (easily), and in SLES11 SP4 at least the tool to make snapshots of OCFS2
> also isn't provided. So the major advantage of having separate LVs for each VM
> is actually gone, making a desaster recovery strategy somewhat difficult. We do
> backups of the files "inside" the VM (just like a physical machine), but once
> your VM images are gone, desaster recovery is a bit tricky, however.
> Maybe it is most efficient to have a SAN-provided "physical" disk for each VM.
> The if the SAN can make snapshots of those disks, you have an elegant backup
> and recovery solution. We had "kind of that" (using iSCSI-provided disks) about
> 15 years ago in SLES10, but the solution was unable to allow loive migration (a
> different and longer story)...
> Regards,
> Ulrich

Hi Ulrich,

my first idea to gave dedicated logical volumes for each guest was just that it looks more tidy.
But as mentioned already i realize that my cluster configuration will grow and grow 
with each further guest and becomes more and more overseeable.

I don't want to create snapshots with lvm, i'm thinking of snapshotting my guests with libvirt
and virsh. I think with that i have a resonable solution. I will snapshot the image files so DR
should be fine.
Do you see any argument which really contradicts to the use of just one logical volume formatted with OCFS2 
for all guests ?
I'm using SLES 12 SP3, SLES 11 SP4 is EOL in a few months.


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