I'm wondering if there are any problems that would occur if you ran a cluster with only two nodes running Pacemaker, but add a third Corosync only node to provide quorum.
I tried this setup, and it appears to work fine after some brief testing; I configured Corosync and votequorum appropriately on all three nodes, but only ever started Pacemaker on two of them. After enabling no-quorum-policy=stop, if I disconnected one of the nodes it would stop itself and the other would take over like I expect, rather than both nodes trying to promote themselves as occurs when there are only two nodes and no-quorum-policy=ignore (for the purposes of debugging and development, I don't have stonith enabled in order to make it easier to monitor what's going on at each node, without my connection dropping due to rebooting the machine). I'm now wondering if there will be any problems I haven't anticipated with this setup, or anything I should look out for. Of course, other options would involve having the third node simply running Pacemaker but permanently in standby, or making it an asymmetric cluster and only allowing any resources to run on the first two nodes. But I'm curious if it's possible to go the simplest possible route and just have corosync running on a third quorum node; or possibly even more. Our setup has a couple of master nodes with large amounts of RAM so that all of the metadata can fit into RAM, and then a number of cheap storage nodes to store the actual bulk data. Because we have the cheap storage nodes, we have a number of machines we can run as quorum-only nodes, but don't want to ever accidentally select them as a master or slave node. Thanks, Brian (as an aside, I'm wondering if this is the right list for this question, or if I should be asking it on the Pacemaker list instead; I haven't quite figured out where questions about interactions between Pacemaker and Corosync should be asked) _______________________________________________ Linux-HA mailing list [email protected] http://lists.linux-ha.org/mailman/listinfo/linux-ha See also: http://linux-ha.org/ReportingProblems
