Changing the Priority of a Standby

If your Failover Manager cluster includes more than one Standby server, you can use the efm set-priority command to influence the promotion priority of a Standby node. Invoke the command on any existing member of the Failover Manager cluster, and specify a priority value after the IP address of the member.

For example, the following command instructs Failover Manager that the acctg cluster member that is monitoring 10.0.1.9 is the primary Standby (1):

efm set-priority acctg 10.0.1.9 1

You can set the priority of a standby to 0 to make the standby non-promotable. Setting the priority of a standby to a value greater than 0 overrides a property value of promotable=false.

For example, if the properties file on node 10.0.1.10 includes a setting of promotable=false and you use efm set-priority to set the promotion priority of 10.0.1.10 to be the standby used in the event of a failover, the value designated by the efm set-priority command will override the value in the property file:

efm set-priority acctg 10.0.1.10 1

In the event of a failover, Failover Manager will first retrieve information from Postgres streaming replication to confirm which Standby node has the most recent data, and promote the node with the least chance of data loss. If two Standby nodes contain equally up-to-date data, the node with a higher user-specified priority value will be promoted to Master. To check the priority value of your Standby nodes, use the command:

efm cluster-status <cluster_name>

Please note: The promotion priority may change if a node becomes isolated from the cluster, and later re-joins the cluster.