The process for adding a control file to a database is similar to the process for deleting one.
The difference is that instead of deleting a file, you create a new copy of an existing file. To add a control file to your database, follow these steps:
- Decide on the location for the new control file. Note: Do not place two control files on the same disk.
- Shut down the database.
- Choose one of the existing control files and copy it to the new location. All control files contain the same information, so it does not matter which one you copy.
- Add the new file that you just created to the list specified by the
control_files entry in your database's initialization parameter file.
- Restart the database.
The key thing to remember is that you must briefly shut down the database while you copy one of the existing control files to a new location. Be
sure that you place your control files on separate disks. The whole point of multiplexing the control file is to protect yourself from the failure
of any one disk. If all your control files are on the same disk, you are defeating that purpose. Moving a control file, as opposed to adding a complete new one, is really a combination of the removal and addition processes. Read more in this
sidebar on moving control files.
The process for moving a control file combines elements from both the process of adding and the process of removing. As far as the physical file
is concerned, you will end up doing both a copy and a delete.
The process for moving a control file looks like this:
- Identify the control file to be moved.
- Decide on the new location for the file.
- Shut down the database.
- Copy the control file to its new location.
- Delete the original file.
- Edit the database's initialization parameter file, find the
control_files entry, and modify the path to the file that you just moved.
- Restart the database.
Again, the key to this procedure is that you make the changes to the physical location of the control files while the database is shut down. When
you restart the database, the initialization parameter file points the Oracle software to the new locations, the control file is opened, and the
database is started.