Perform a Manual Changeover on a Multi-Server System

On multi-server systems such as Hot-Standby Pair and Triple Standby, you will need to perform a manual changeover; a user initiated changeover that sets a Standby server to switch to Main. You will need to perform a manual changeover after configuring the servers so that the Main and Standby server(s) can switch to Main when needed. We also recommend that you perform manual changeovers on a regular basis at times when system activity is low (and so the changeover will not have a major effect on the running of the system).

On a Hot-Standby Pair system, a manual changeover will set the Standby server to Main.

On a Triple Standby system, a manual changeover will set one of the Standby servers to Main. For this reason, you will need to perform two manual changeovers when you are first testing that the servers in the architecture can switch to Main—one changeover for the connection between the Main and Standby 1 and one changeover for the connection between Standby 1 and Standby 2.

To perform a manual changeover:

1. Access the server that is running as the Main server.
2. Stop or restart the server that is running as the Main server (see Start and Stop the System Server).
3. If you are working on a Hot-Standby Pair system, stopping or restarting the Main server will cause the Standby server to switch to Main. When the server that began as the Main server restarts, the two servers will arbitrate to determine which server remains as Main and which is the Standby (see Define the Server’s Arbitration Priority).
4. If you are working on a Triple Standby system, stopping or restarting the Main server will cause the two Standby servers to arbitrate. One of the Standby servers will switch to Main while the other will remain as a Standby. The two servers will then work as a Hot-Standby Pair until the Main server is restored. If you are testing the server architecture for the first time, you should perform another manual changeover, only this time stop the server that is running as Main (i.e. the Standby server that switched to Main after the previous changeover). This second changeover will result in the remaining Standby server switching to Main.
3. Restart any servers that have been stopped. This will allow you to check that the servers in the architecture are running correctly, as Main or Standby.