On 3 Sep 2014, at 9:29 am, Brian Campbell <brian.campb...@editshare.com> wrote:
> 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. Its supposed to work and I've not heard anyone complain lately that it doesn't (possibly because no-one tried recently). If you encounter any problems, definitely let us know. > > 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 > Linux-HA@lists.linux-ha.org > http://lists.linux-ha.org/mailman/listinfo/linux-ha > See also: http://linux-ha.org/ReportingProblems
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