On 2018-06-20 11:52 PM, Andrei Borzenkov wrote: > 21.06.2018 00:50, Digimer пишет: >> On 2018-06-20 05:46 PM, Jehan-Guillaume de Rorthais wrote: >>> On Wed, 20 Jun 2018 17:24:41 -0400 >>> Digimer <li...@alteeve.ca> wrote: >>> >>>> Make sure quorum is disabled. Quorum doesn't work on 2-node clusters. >>> >>> It does with the "two_node" parameter enabled in corosync.conf...as far as I >>> understand it anyway... >> >> It doesn't, that option disables quorum in corosync. >> > > This option does not disable quorum - this option fakes quorum so > corosync continues to report "in quorum" even when one node is lost. it > is quite possible that pacemaker quorum does not map one-to-one to > corosync quorum though.
Technically correct, which is the best kind of correct. I didn't go into that detail as the results are the same (and consistent with pacemaker's quorum=false language). >> Quorum is floor(($nodes / 2) + 1). So in a 3-node, that is 3 -> 1.5 -> >> 2.5 -> 2 votes needed for quorum. In a 2-node, that is 2 -> 1 -> 2 -> 2 >> votes needed for quorum, meaning you can't lose a node to operate (which >> is kinda not HA :) ). >> > > Yes, but that assumes normal, non two_node, configuration. As said, > two_node makes corosync to always pretend quorum is available (after > initial implicit wait_for_all). > _______________________________________________ > Users mailing list: Users@clusterlabs.org > https://lists.clusterlabs.org/mailman/listinfo/users > > Project Home: http://www.clusterlabs.org > Getting started: http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf > Bugs: http://bugs.clusterlabs.org > -- Digimer Papers and Projects: https://alteeve.com/w/ "I am, somehow, less interested in the weight and convolutions of Einstein’s brain than in the near certainty that people of equal talent have lived and died in cotton fields and sweatshops." - Stephen Jay Gould _______________________________________________ Users mailing list: Users@clusterlabs.org https://lists.clusterlabs.org/mailman/listinfo/users Project Home: http://www.clusterlabs.org Getting started: http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf Bugs: http://bugs.clusterlabs.org
