[linux-lvm] CLVM Snapshot HOWTO?
vu at sivell.com
Tue Mar 24 03:34:16 UTC 2009
Paul Dugas wrote:
> I apologize if this has been covered already or is written up elsewhere
> but I can't seem to find it. I've got a couple of AoE volumes that I'm
> using for LVM VGs. They have GFS filesystems on LVs that are sized to
> fill 90% of the the VGs; 10% space left over for snapshots. I have 4
> CENTOS 5.2 machines clustered and mounting the GFS filesystems. That's
> working well.
> Having used LVM snapshots in non-cluster environments before, I figured
> I'd just use the same logic for backing up the volumes; lvcreate -s,
> mount, backup, umount, lvremove. This quickly fell apart and I started
> to think about it more. I ended up wondering how snapshots of the
> volume could ever really work without coordinating with the other
> My question is this. Should I be able to use snapshots on clustered
> volumes like this? If not, are there plans to support it later? If so,
> can someone point me to a working example?
I think you have to freeze the GFS volume before you create a snapshot,
then you unfreeze it. man gfs_tool
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