[ClusterLabs] design of a two-node cluster

Lentes, Bernd bernd.lentes at helmholtz-muenchen.de
Tue Dec 15 18:35:16 EST 2015

Digimer wrote:
> To prevent a dual fence, where both nodes fence each other when
> communication between the nodes fail but the nodes are otherwise
> healthy, you need to set a fence delay against one of the nodes. So when
> this happens, if the delay is on node 1, this will happen;
> Node 1 looks up how to fence node 2, sees no delay and fences
> immediately. Node 2 looks up how to fence node 1, sees a delay and
> pauses. Node 2 will be dead long before the delay expires, ensuring that
> node 2 always loses in such a case. If you have VMs on both nodes, then
> no matter which node the delay is on, some servers will be interrupted.
Ok. The setp for the ressources is clear now.
What is about fencing, quorum, STONITH ?
Are there other possibilities than the mentioned fence delay ?
When the interconnect between the nodes goes down, i have a split brain.
In every node i have two eth's which will be combined to a bond.
I have two possibilities to fence, HP ILO and an APC Power switch which is configurable over network.
What i read already is that in a two-node cluster i have to diable quorum.
What is about a quorum disk ? I also read about "tiebrakers" or that STONITH is magically able to chosse the right
node to fence (i can't believe that).


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