[Linux-cluster] rhel6 node start causes power on of the other one

Digimer linux at alteeve.com
Tue Mar 22 15:23:14 UTC 2011

On 03/22/2011 06:12 AM, Gianluca Cecchi wrote:
> If the initial situation is both nodes down and I start one of them, I
> get it powering on the other, that is not my intentional target...
> Is this an expected default behaviour in rh el 6 with two nodes
> without quorum disk? Or in general no matter if a quorum disk is
> defined?
> If so, how to change it if possible?

This behaviour is by design and is expected in 2-node scenarios.

The reason is that each node can, effectively, have quorum. So on boot,
if it can't talk to it's partner node, it has no way of knowing if it is
safe to start cluster services. So it has to assume the worst and fence
the other node. As most people set their fence action to 'reboot', the
other node will boot.

To avoid this behaviour, change the fence action to 'poweroff'. Of
course, this means that a failed node will never auto-recover.

Also, the time it takes for the cluster to give up waiting for the other
node is defaulted to 6 seconds. You can control this with the
<fencesdaemon post_join_delay="x" />. I personally prefer setting this
to 60 seconds, to give plenty of time to start both nodes. The value you
choose should best suit your needs.

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