[Pacemaker] Resource Agents 1.0.4: HA LVM Patch

Ulf mopp at gmx.net
Wed Apr 27 03:40:22 EDT 2011

I'm not sure if inux-ha-dev at lists.linux-ha.org will receive this message, as I'm not subscribed to.

>Can you please elaborate on the benefits this patch would bring.
>Is it supposed to prevent a VG from being mounted on more than
>one node?

Following scenario: Shared storage with a VG and a not clusteraware filesystem like ext3. An active/passive cluster.
During the reboot of a server many distributions do a "vgscan --mknodes", which will activate the VG.
The result will be an active VG on the passive node. You really want to avoid a non cLVM VG to be active on two nodes.
There might be some other trick with a filter to get this working, but the volume_list is the preferred solution, at least in my eyes.
The volume_list method is a way to prevent a non cLVM VG to be active on more than one node.

The solution has only one caveat. A VG remains active even if it looses the VG tag, so you make sure the node get STONITH.

To get this working you need to add tages to /etc/lvm/lvm.conf
tags { hosttags = 1 }

And create a /etc/lvm/lvm_HOSTNAME.conf, which needs to be individual on every node. Add the line to enable the rootvg and every VG which is tagged with the hostname.
activation { volume_list = [ "rootvg", "@HOSTNAME" ] }

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