Control file recovery

Control file needs recovery when

• Any one control file specified in a parameter file is lost due to media failure or corrupted
• New control file is needed when changing the database

When one control file becomes corrupted, oracle database automatically stops running. One can determine which control file is causing a problem by looking into alert log file. Then remove the corrupted control file and copy good control file to the corrupted location

1. rm -f /u10/oradata/controlfile01.ctl
   

2. cp /u20/oradata/controlfile02.ctl /u10/oradata/controlfile01.ctl
   

3. Then mount the database

   STARTUP MOUNT;
   

4. and open it

   ALTER DATBASE OPEN;
   

When a control file is lost, copy a good control file to the new location, modify control_file parameter by removing lost location and add the new location to it:

1. Shutdown the database:

   SHUTDOWN ABORT;
   

2. cp /u20/oradata/controlfile02.ctl /u10/oradata/controlfile04.ctl
   

3. modify PFILE:

   CONTROL_FILE='/u20/oradata/controlfile02.ctl',
   '/u21/oradata/controlfile03.ctl',
   '/u30/oradata/controlfile04.ctl'
   

4. Then mount and open the database:

   STARTUP MOUNT;
   ALTER DATBASE OPEN;