[Pacemaker] Split-site cluster in two locations

[Andrew Beekhof]

On Tue, Dec 28, 2010 at 10:21 PM, Anton Altaparmakov <aia21 at cam.ac.uk> wrote:
> Hi,
>
> On 28 Dec 2010, at 20:32, Michael Schwartzkopff wrote:
>> Hi,
>>
>> I have four nodes in a split site scenario located in two computing centers.
>> STONITH is enabled.
>>
>> Is there and best practise how to deal with this setup? Does it make sense to
>> set expected-quorum-votes to "3" to make the whole setup still running with
>> one data center online? Is this possible at all?
>>
>> Is quorum needed with STONITH enabled?
>>
>> Is there a quorum server available already?
>
> I couldn't see a quorum server in Pacemaker so I have installed a third dummy node which is not allowed to run any resources (using location constraints and setting the cluster to not be symmetric) which just acts as a third vote.  I am hoping this effectively acts as a quorum server as a node that looses connectivity will lose quorum and shut down its services whilst the other real node will retain connectivity and thus quorum due to the dummy node still being present.
>
> Obviously this is quite wasteful of servers as you can only run a single Pacemaker instance on a server (as far as I know) so that is a lot of dummy servers when you run multiple pacemaker clusters...  Solution for us is to use virtualization - one physical server with VMs and each VM is a dummy node for a cluster...

With recent 1.1.x builds it should be possible to run just the
corosync piece (no pacemaker).

>
> Best regards,
>
>        Anton
>
>>
>> Thanks for any hints,
>>
>> Greetings!
>>
>> --
>> Dr. Michael Schwartzkopff
>> Guardinistr. 63
>> 81375 München
>>
>> Tel: (0163) 172 50 98
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>
> Best regards,
>
>        Anton
> --
> Anton Altaparmakov <aia21 at cam.ac.uk> (replace at with @)
> Unix Support, Computing Service, University of Cambridge, CB2 3QH, UK
> Linux NTFS maintainer, http://www.linux-ntfs.org/
>
>
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> Project Home: http://www.clusterlabs.org
> Getting started: http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf
> Bugs: http://developerbugs.linux-foundation.org/enter_bug.cgi?product=Pacemaker
>