Configuring RMAN - Oracle RMAN for Absolute Beginners - page 105

I don't usually use the default location or the FRA for control file autobackups. I prefer these backups to be placed
in the same directory the database backups are in. Here is an example:

RMAN> configure controlfile autobackup format for device type disk to
'/u01/ORA12C/rman/rman_ctl_%F.bk';

If you want to set the autobackup format back to the default, do so as follows:

RMAN> configure controlfile autobackup format for device type disk clear;

8. Backing Up Archive Redo Logs
You should back up your archive redo logs on a regular basis. The archivelog files shouldn't be removed from disk
until you've backed them up at least once. I usually like to keep on disk any archive redo logs that have been generated
since the last good RMAN backup.
Generally, I instruct RMAN to back up the archive redo logs while the data files are being backed up. This is a
sufficient strategy in most situations. Here is the command to back up the archive redo logs along with the data files:

RMAN> backup database plus archivelog;

Sometimes, if your database generates a great deal of redo, you may need to back up your archive redo logs at a
frequency different from that of the data files. DBAs may back up the archive redo logs two or three times a day; after
the logs are backed up, the DBAs delete them to make room for more current archivelog files.
In most situations, you don't need any archive redo logs that were generated before your last good backup. For
example, if a data file has experienced media failure, you need to restore the data file from a backup and then apply
any archive redo logs that were generated during and after the backup of the data file.
On some occasions, you may need archive redo logs that were generated before the last backup. For instance, you
may experience a media failure, attempt to restore your database from the last good backup, find corruption in that
backup, and therefore need to restore from an older backup. At that point, you need a copy of all archive redo logs that
have been generated since that older backup was made.

9. Determining the Location for the Snapshot Control File
RMAN requires a read-consistent view of the control file for the following tasks:

• Synchronizing with the recovery catalog

• Backing up the current control file

RMAN creates a snapshot copy of the current control file that it uses as a read-consistent copy while it's
performing these tasks. This ensures that RMAN is working from a copy of the control file that isn't being modified.
The default location of the snapshot control file is OS specific. On Linux platforms the default location/format is
ORACLE_HOME/dbs/snapcf_@.f . Note that the default location isn't in the FRA (even if you've implemented an FRA).
You can display the current snapshot control file details, using the SHOW command:

RMAN> show snapshot controlfile name;