Use host names or IP addresses as values in failover.properties. The following table describes what happens in certain scenarios when using the automatic failover feature:
|The default password for dmuser has been changed on any of the servers specified in failover.properties.||SSH setup fails, which prevents the active-standby components from starting correctly.|
|Invalid host names are specified in failover.properties.||The SSH setup fails.|
|Config is run as a user other than ROOT.||The SSH setup fails.|
|The dm.rest.endpoint is not modified in commandline.properties.||The command line is not able to connect to a standby REST server when the active REST server becomes unavailable.|
|The broker.url is not modified in daemon.properties and agent.properties.||The daemon and agent are not able to connect to a standby JMS broker when the active JMS broker becomes unavailable.|
|The sync.ismaster value in sync.properties is not set correctly on both active and standby sync servers.||The sync monitor service does not start correctly.|
|The active sync monitor become unavailable when the cluster is running in active mode.||Check the synchronization and Postgres logs on the designated active daemon server to diagnose the root cause of the issue. See Fixing Sync Service with High Availability.|
|Both daemon servers become unavailable after failover monitoring has been enabled.||The monitoring service detects the active daemon server failure and initiates a failover sequence on the standby daemon server. If it is unable to connect to the standby daemon server, it exits and the components need to be reconfigured and restarted using the dmcluster switchback command from the designated-active daemon server once the servers are up.|
|The designated-active daemon becomes unavailable and a failover has been initiated. The daemon is restarted again using the dmdaemon service script.||The monitoring service notices two daemons running and stops the daemon on the designated active server. To properly restore the unavailable daemon, use the dmcluser switchback command on the designated active server.
For more information, see Failing Back to the Designated-Active Daemon.
|The standby daemon is started using the dmdaemon service script when the designated-active daemon is still running.||The monitoring service notices two daemons running and stops the daemon on the designated standby server. Components on the designated standby servers cannot be started when the designated active server is running in active mode. If a permanent change of servers is necessary, reconfigure the Data Mover cluster using the dmcluster config command on the server to become the new designated active server.|
|The JMS broker on the designated-active daemon server becomes unavailable.||Failover occurs if ActiveMQ cannot be started by the failover service after a multiple attempts.|
|ActiveMQ on the designated-standby daemon starts.||Failover stops the service automatically. Components on the designated standby servers cannot be started when the designated active server is running in active mode. If a permanent change of servers is necessary, reconfigure the Data Mover cluster using the dmcluster config command on the server to become the new designated-active server.|