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<p class="MsoNormal">Hello all,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I have a two-node Pacemaker cluster configured with a high-availability PostgreSQL resource. Occasionally, I notice that when the Master/primary DB is running under significant write load, the cluster “monitor” operation will time out,
thus incrementing the failcount for the ha-db resource. This happened again recently, and the running primary DB was demoted and then re-promoted to be the running primary. What I’m having trouble understanding is why the running Master/primary DB was
demoted. After the monitor operation timed out, the failcount for the ha-db resource was still less than the configured “migration-threshold”, which is set to 5.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Here's some information on the cluster and the scenario:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">OS: RHEL 7.9<o:p></o:p></p>
<p class="MsoNormal">Corosync: 2.4.5-7<o:p></o:p></p>
<p class="MsoNormal">Pacemaker: 1.1.23-1<o:p></o:p></p>
<p class="MsoNormal">PAF resource agent: 2.3.0<o:p></o:p></p>
<p class="MsoNormal">Master DB node: dbsrv2<o:p></o:p></p>
<p class="MsoNormal">Standby DB node: dbsrv1<o:p></o:p></p>
<p class="MsoNormal">Other resources: fencing and VIP<o:p></o:p></p>
<p class="MsoNormal">Cluster resource defaults:<br>
migration-threshold=5<o:p></o:p></p>
<p class="MsoNormal"> resource-stickiness=10<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">The overall scenario is this:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<ul style="margin-top:0in" type="disc">
<li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level1 lfo1">The Master/primary DB is running on node dbsrv2<o:p></o:p></li><li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level1 lfo1">A monitoring timeout occurs on node dbsrv2<o:p></o:p></li><li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level1 lfo1">The master resource for node dbsrv2 is incremented from 2 to 3 (there were 2 other failures days before)<o:p></o:p></li><li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level1 lfo1">The master DB is demoted to standby (i.e. stopped and restarted) on node dbsrv2<o:p></o:p></li><li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level1 lfo1">Node dbsrv2 is re-promoted to Master/primary, with the failcount remaining at 3<o:p></o:p></li></ul>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">My expectation was that no demotion should have occurred until the migration threshold was met. Any help in explaining why the running primary was demoted would be appreciated!<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I’ve attached the corosync log from the time period this occurred. The scenario I described starts at 20:55 on 2/16/22 in the log.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thanks,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Larry<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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