[Pacemaker] Very strange behavior on asymmetric cluster

Pavel Levshin pavel at levshin.spb.ru
Wed Mar 16 13:32:33 EDT 2011

16.03.2011 10:29, Andrew Beekhof:
>> I still don't understand why it monitors services by default on all nodes
>> when the cluster is assymetrical
> Because we don't just make assumptions about what the state of the
> cluster is - we verify them.

Actually, you verify what misconfigured or fake resource agents are 
saying. Very sane check, indeed.

Take DRBD for example. Any resource may be configured on no more than 
two nodes. If there are more nodes in the cluster, N-2 of them will 
check for nothing, fail to check from time to time and cause service 
instability. Imagine a highly overloaded or broken node where all, 
including fake, resource agents are failing to respond in timely manner. 
Every service in such a cluster may suffer from this problem.

Well, your approach to monitoring is reasonable for symmetrical cluster.

I beg your pardon if my objections are inappropriate.

Pavel Levshin

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