[Linux-cluster] HA-LVM Configuration & Snapshots

[Manish Kathuria]

On a two node (active-passive) cluster with external storage on RHEL
6.1, we need to use Snapshots for taking backup of the logical volumes
on the storage. As per the documentation, snapshots are not supported
on clustered logical volumes (using CLVM).  Since each of the logical
volumes on the external storage are going to be exclusively mounted
(and used) by a single node at any point of time, we can therefore use
HA-LVM instead of CLVM. However, for configuring HA-LVM also, there
are two suggested methods
(https://access.redhat.com/kb/docs/DOC-3068):

- first one is the simpler one, using the CLVM variant while the other
one is the original method using volume_list and VG tags.

I have a few queries related to both.

Do snapshots work if we configure HA-LVM using CLVM  and run the clvmd daemon ?

In case of the original HA-LVM configuration method, can we leave the
volume_list in  /etc/lvm/lvm.conf blank since we are not going to have
any shared VGs or LVs except for those which are going to be shared
using HA-LVM.

Thanks,
--
Manish