6.15.1. Performing Maintenance on a Single Replica

Performing maintenance on a single Replica can be achieved by temporarily shunning the Replica (while in AUTOMATIC policy mode) and doing the necessary maintenance. Shunning a datasource in this way will temporarily remove it from the dataservice, and prevent active and new connections from using the datasource for operations.

The steps are:

  1. Shun the Replica:

    [LOGICAL:EXPERT] /alpha > datasource host2 shun

    Shunning a datasource does not put the replicator offline, so the replicator should also be put in the offline state to prevent replication and changes being applied to the database:

    [LOGICAL:EXPERT] /alpha > replicator host2 offline
  2. Perform the required maintenance, including updating the operating system, software or hardware changes.

  3. Validate the server configuration :

    shell> tpm validate
  4. Recover the Replica back to the dataservice:

    [LOGICAL:EXPERT] /alpha > datasource host2 recover

Once the datasource is added back to the dataservice, the status of the node should be checked to ensure that the datasource has been correctly added back, and the node is ONLINE and up to date.

While the datasource is shunned, the node can be shutdown, restarted, upgraded, or any other maintenance. Throughout the process, the Replica should be monitored to ensure that the datasource is correctly added back into the dataservice, and has caught up with the Primary. Any problems should be addressed immediately.