[Pacemaker] Clustered LVM in failover cluster

[David Morton]

So if we do not use clustered VG's will any changes made to a shared disk
(non clustered filesystem) be visible to all cluster nodes ? Or does
activating the VG resource effectively 'refresh' the LVM layout prior to
any filesystem actions taking place in the event of a failover ?

We will have one OCFS2 volume so DLM and cLVM are requirements there either
way.

On Mon, Sep 10, 2012 at 8:44 PM, Lars Marowsky-Bree <lmb at suse.com> wrote:

> On 2012-09-10T11:06:15, David Morton <davidmorton78 at gmail.com> wrote:
>
> > Not directly Pacemaker related but a simple question for those who manage
> > clusters ...
> >
> > I'm recreating our failover cluster on a new SAN which will use cLVM and
> > XFS, I am after some clarification that the "--clustered y" directive is
> > the correct and appropriate way to create the volume groups as the LVM
> > layout will be visible to both cluster nodes at all times regardless of
> the
> > filesystem mount state ?
> >
> > I'll then create LVM resources in Pacemaker to control the activation of
> > the volume groups prior to filesystem mounting.
>
> If you're using an LVM resource to activate/deactivate the VG in a
> fail-over setting, there is no need to use a clustered volume group.
>
> You gain some protection against admin mistakes by not exposing the VG,
> and if you do not need concurrent access to the VG, you can skip using
> the DLM/cLVM2, which reduces complexity.
>
>
> Regards,
>     Lars
>
> --
> Architect Storage/HA
> SUSE LINUX Products GmbH, GF: Jeff Hawn, Jennifer Guild, Felix
> Imendörffer, HRB 21284 (AG Nürnberg)
> "Experience is the name everyone gives to their mistakes." -- Oscar Wilde
>
>
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