Recover Oracle using an Offline Backup with RMAN

 

Recover Oracle using an Offline Backup with RMAN

 

Before you can restore your database using RMAN, the following needs to be properly in place (this assumes a full system loss):

* The operating system must be installed

* The Oracle software must be installed

* The RMAN backup files must be available

* You must create the file systems that the database files will be restored to.

Once these pieces are in place you can restore your database. In the event of a full system loss you will need to replace:

* The SPFILE

* The Control File

* The database datafiles

If the SPFILE or control file is intact, you will not need to replace that component.

Restoring the Oracle SPFILE

Restoring the SPFILE is an automated process in many cases with RMAN. You simply need to configure RMAN with the proper database DBID (which you should have recorded when you created the database) and you can then restore the SPFILE from any auto backup.

To restore the spfile, you still need to start the database, but you can do so with a minimal database parameter file. All you need to do is start your database instance is set the db_name parameter in a manual parameter file. Then you can start the instance using the startup command with the pfile parameter as seen in this

example:

Startup nomount pfile=c:\u01\app\oracle\product\12.1.0.2\database\initstand.ora

 

Once the instance is started, you can start RMAN and restore the SPFILE as seen in this example:

RMAN>restore spfile from autobackup;

 

Restoring the Oracle Control File

Restoring the control file is much like restoring the SPFILE. Again, you simply need to configure RMAN with the proper database DBID and you can then restore the control file from any auto backup.

To restore the control file, you still need to start the database, but you can do so with a minimal database parameter file. All you need to do is start your database instance is set the db_name parameter in a manual parameter file. Then you can start the instance using the startup command with the pfile parameter as seen in this example:

Startup nomount pfile=c:\u01\app\oracle\product\12.1.0.2\database\initstand.ora

 

Once the instance is started, you can start RMAN and restore the CONTROL FILE as seen in this example:

RMAN>restore controlfile from autobackup;

 

Restoring and Recovering the Database

Once you have recovered the SPFILE and the control file, restoring the database can be pretty easy. Again, many things can occur to make the process more complex, but assuming that you have restored your RMAN backup sets in the same place, and that all of your file systems are built correctly, and named the same as before, your restore the database with the following command:

RMAN>recover database noredo;

If the online archived redo logs are available, then change the command to the following:

RMAN>restore database;

Once the database is restored, you can then recover the database. Simply use the RMAN recover database command as seen here:

RMAN>recover database;

Once you have issued this command, your database should be recovered to the point of the backup.

Recover your Database using an Online Backup with RMAN

If you backed up your ARCHIVELOG mode database with RMAN then you will be able to recover to the point of the last available archived redo log (or online redo log if those are still available). The cool thing is that the RMAN procedure is almost the same regardless of if the backup was in ARCHIVELOG mode or NOARCHIVELOG mode.

First, follow the directions above for restores of the SPFILE and the control file. Now, simply use the restore database and recover database commands as seen here:

RMAN>restore database;

RMAN>recover database;

Again, Oracle will restore your database. It will also automatically recover the archived redo logs for you, so you don't have to worry about it.