Men&Mice Central HA tweaks

Changing the default heartbeat timestamp value in Central HA

The local time of the cluster member machines are used to update the heartbeat timestamp in the database. It’s crucial that the cluster member machines have a synchronized time.

By default the Central instances update the heartbeat timestamp in the database every 10 seconds, as set in the /var/mmsuite/mmcentral/preferences.cfg file:

1<HeartbeatInterval value=“10” />

This can be tweaked between values of 5 and 15.

When a Central instance stops to write the heartbeat timestamp to the DB the HeartbeatMaxAllowedDowntime value is used to determine if a failover is done to the next valid Central in the list. (Valid meaning, in this case, that the next Central application is a HA cluster member and is writing its heartbeat timestamp to the database.)

The default maximum downtime is set for 30 seconds. When the current time [UTC – heartbeat timestamp UTC] > [HeartbeatMaxAllowedDowntime] an automatic failover is triggered.

The default maximum downtime can be overwritten in the /var/mmsuite/mmcentral/preferences.cfg for each Central instance:

1<HeartbeatMaxAllowedDowntime value=“30” />

Values between 20 and 120 are allowed, setting the maximum downtime to 20-120 seconds.