[Linux-cluster] CLVM and snapshot: test results and questions
xavier.montagutelli at unilim.fr
Sat Jan 23 08:26:56 UTC 2010
On Friday 22 January 2010 18:33:01 Dirk H. Schulz wrote:
> Hi all,
> according to RedHat's docs creating snapshots in a cluster environment
> should be basically possible.
> Here is what the "Cluster_Logical_Volume_Manager.pdf" says on page 49:
> > LVM snapshots are not cluster-aware, so they require exclusive access
> > to a volume. For information
> > on activating logical volumes on individual nodes in a cluster, see
> > Section 8, “Activating
> > Logical Volumes on Individual Nodes in a Cluster”.
> So now I tried "lvcreate ... -s ..." on node 1 to create a snapshot, but
> received the standard error that shapshots of clustered volumes are not
> implemented yet.
> Now there is 2 possibilities how this could be understood:
> 1. lvcreate refuses snapshotting cluster logical volumes if the cluster
> bit is there - disregarding the exclusivity of the activation state.
> 2. I did something wrong or incomplete.
> I really would regret number 1 being true, and because of the errors I
> received inbetween I hope that 2 comes up as winner. :-)
> E.g. on HPUX you have to activate the volume group exclusively, not the
> logical volume. Could that be the reason.
> Is anyone out there who can shed enough light on all this?
A word of warning : I am not an expert.
Unfortunately the answer #1 seems to be the good one ...
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