Recovering a Control File Using a Current Copy

This section presents ways that you can recover your control file from a current backup or from a multiplexed copy.

Recovering from Control File Corruption Using a Control File Copy

This procedure assumes that one of the control files specified in the CONTROL_FILES parameter is corrupted, that the control file directory is still accessible, and that you have a multiplexed copy of the control file.

With the instance shut down, use an operating system command to overwrite the bad control file with a good copy:
```
% cp /u03/oracle/prod/control03.ctl  /u02/oracle/prod/control02.ctl
```
Start SQL*Plus and open the database:
```
SQL> STARTUP
```

Recovering from Permanent Media Failure Using a Control File Copy

This procedure assumes that one of the control files specified in the CONTROL_FILES parameter is inaccessible due to a permanent media failure and that you have a multiplexed copy of the control file.

With the instance shut down, use an operating system command to copy the current copy of the control file to a new, accessible location:
```
% cp /u01/oracle/prod/control01.ctl  /u04/oracle/prod/control03.ctl
```

Edit the CONTROL_FILES parameter in the initialization parameter file to replace the bad location with the new location:

CONTROL_FILES = (/u01/oracle/prod/control01.ctl,
                 /u02/oracle/prod/control02.ctl, 
                 /u04/oracle/prod/control03.ctl)

Start SQL*Plus and open the database:
```
SQL> STARTUP
```

If you have multiplexed control files, you can get the database started up quickly by editing the CONTROL_FILES initialization parameter. Remove the bad control file from CONTROL_FILES setting and you can restart the database immediately. Then you can perform the reconstruction of the bad control file and at some later time shut down and restart the database after editing the CONTROL_FILES initialization parameter to include the recovered control file.