Master Fails While Backup Is in a Failed State

Under this condition, if you restart the Environment Display on the master server, the redundancy manager does not start because the master server cannot communicate with the other server.

To recover from master server failure

1. Open the Environment Display dialog box.

2. On the File menu, click Force System to Master.

   This action manually forces the viable server to become the master.

3. On the File menu, click Exit and Shutdown.

4. Restart the Environment Display.

   This server assumes the role of master and operates as a standalone server until the backup server is restored to an operational state.

   Note: Do not start the failed master as the backup until the problem that caused the failure is repaired.

If the server does not have a redundancy state of Master with Valid Backup, or if you are not using redundancy and IBCli loses communications with the control system, IBCli continues trying to read valid tag values.

The read error is not reported more than one time per tag. Read errors on tags that have never had a successful read only report the error one time and redundancy is not initiated.

This design ensures that improperly-linked tags do not initiate a redundancy switch-over.

If communication between the control system and IBCli fails (that is, IBCli is still running but cannot communicate), an automatic switch-over to the backup server does not occur. IBCli issues Read Failed errors for the linked tags that are attempting to be read. If this action occurs, an operator must determine the cause of the failure and then determine if a manual switch-over to the backup server can resolve the communication fault.