Adding or dropping redo logs to the standby database

If adding redo logs groups or redo logs members to the primary database, what should be done on the standby database?

To add normal redo logs (not standby redo logs) to a primary database, the new redo logs definitions must also be added to the standby database.

A standby database does not have redo logs so they cannot be added with the same SQL (ALTER DATABASE ADD STANDBY LOGFILE) commands as on the primary database. A standby database will only have redo logs when the standby database is activated to become a primary database. The activation process will create the redo logs.

The redo log information is held in the controlfile information on the primary database, so we can replace the standby controlfile with a new controlfile to automatically have the new redo log information available on the standby database.

This can be done in Dbvisit with the following command:

dbv_functions -Q database

Where database is your database name. This command is only run on the primary server.

This command will:

  • Shutdown the standby database (It will not shutdown the primary database)
  • Recreate the standby controlfile on standby server from the controlfile on the primary server.
  • Restart the standby database.

Notes:

  1. Ensure that the standby database is up to date before running this command.
  2. The standby database must have the same structure as the primary database. If this is not the case, then the controlfile information has to be updated on the standby database once the controlfile has been replaced with the command: 
    SQL> alter database rename file 'x' to 'y';

    Each datafile or redo file that is in a different location to the primary has to be renamed.