[Pacemaker] RHEL6.x dependency between 2-node-settings for cman and quorum settings in pacemaker

[Andrew Beekhof]

On 12/04/2013, at 4:58 PM, Andreas Mock <Andreas.Mock at web.de> wrote:

> Hi all,
> 
> another question rised up while reading documentation concerning
> 2-node-cluster under RHEL6.x with CMAN and pacemaker.
> 
> a) In the quick start guide one of the things you set is
> CMAN_QUORUM_TIMEOUT=0 in /etc/sysconfig/cman to get one
> node of the cluster up without waiting for quorum. (Correct
> me if my understanding is wrong)
> 
> b) There is a special setting in cluster.conf
>  <cman two_node="1" expected_votes="1" >
>  </cman>
> which allows one node to gain quorum in a two node cluster
> (Please also correct me here if my understanding is wrong)
> 
> c) And there is a pacemaker setting
> no-quorum-policy which is mostly set to 'ignore' in all startup
> tutorials.
> 
> My question: I would like to understand how these settings
> influence each other and/or are dependent.

a) allows "service cman start" to complete (and therefor allow "service pacemaker start" to begin) before quorum has arrived.
b) is a possible alternative to a) but I've never tested it because it is superseded by c) and in fact makes c) meaningless since the cluster always has quorum.

a+c is preferred for consistency with clusters of more than 2 nodes.

> 
> As most insight as possible appreciated. ;-)
> 
> Best regards
> Andreas
> 
> 
> 
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