[Linux-cluster] recommended method for changing quorum device

[Digimer]

On 05/31/2011 03:35 PM, bergman at merctech.com wrote:
> I've got a 3-node RHCS cluster and the quorum device is on a SAN disk
> array that needs to be replaced. The relevent versions are:
>
>        CentOS 5.6 (2.6.18-238.9.1.el5)
>        openais-0.80.6-28.el5_6.1
>        cman-2.0.115-68.el5_6.3
>        rgmanager-2.0.52-9.el5.centos.1
>
>
> Currently the cluster is configured with each node having one vote and
> the quorum device having 2 votes, to allow operation in the event of
> multiple node failures.
>
> I'd like to know if there's any recommended method for changing the
> quorum disk "in place", without shutting down the cluster.
>
> The following approaches come to mind:
>
>        1. Create a new quorum device (multipath, mkqdisk).
>
>           Ensure that at least 2 of the 3 nodes are up.
>
>           Change the cluster configuration to use the new path to
>           the new device instead of the old device.
>
>           Commit the change to the cluster.
>
>        2. Create a new quorum device (multipath, mkqdisk).
>
>           Ensure that at least 2 of the 3 nodes are up.
>
>           Change the cluster configuration to not use any quorum
>           device.
>
>           Commit the change to the cluster.
>
>           Change the cluster configuration to use the new quorum
>           device.
>
>           Commit the change to the cluster.
>
>        3. Create a new quorum device (multipath, mkqdisk).
>
>           Change the cluster configuration to use both quorum
>           devices.
>
>           Commit the change to the cluster.
>
>              --------------------------------------------------
>              Note: the 'mkqdisk' manual page (dated July 2006)
> 	    states:
>                    using multiple different devices is currently
>                    not supported
>              Is that still accurate?
>              --------------------------------------------------
>
>           Change the cluster configuration to use just the
>           new quorum device instead of the old device.
>
>           Commit the change to the cluster.
>
> Thanks for any suggestions.
>
> Mark

With the caveat that I have not done this and make no claims to being an 
expert; Option 2 strikes me as the best choice.

-- 
Digimer
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