[Linux-cluster] CLVM and snapshot: test results and questions

[Xavier Montagutelli]

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 ...

http://archives.free.net.ph/message/20081014.081254.df482534.en.html

Latest thread on "linux-lvm" ML :

https://www.redhat.com/archives/linux-lvm/2010-January/msg00007.html

-- 
Xavier Montagutelli                      Tel : +33 (0)5 55 45 77 20
Service Commun Informatique              Fax : +33 (0)5 55 45 75 95
Universite de Limoges
123, avenue Albert Thomas
87060 Limoges cedex