About RMAN

RMAN backup is a physical backup method. There are two other methods of backup and recovery in Oracle database: user-managed and Oracle EXPORT utility. The EXPORT utility is essentially a logical backup utility that performs backups only on the logical components of the database.

RMAN> show all; //will show all configuration parameters

Error messages are reported in the V$RMAN_OUPUT
Status of RMAN backups in V$RMAN_BACKUP_JOB_DETAILS

Some commonly used configuration settings that help you use RMAN.
DEVICE TYPE
BACKUP TYPE
COMPRESSED BACKUPSET
CHANNEL DISK DEVICE
CHANNEL TAPE DEVICE

To configure default device to tape and then to disk
RMAN> configure default device type to sbt;
RMAN> configure default device type to disk;

To configure default backup type for an image copy and then for a backup set
RMAN> configure device type disk backup type to copy;
RMAN> configure device type disk backup type to backupset;

To configure a default device for either tape or disk to a compressed backup set
RMAN> configure device type disk backup type to compressed backupset
RMAN> configure device type sbt backup type to compressed backupset;

Some RMAN format options:
%d specifies the name of the database
%f specifies absolute file number
%l specifies DBID
%N tablespace name
%s backup set number
%p specifies piece number within the backup set
%t backup set timestamp

Ex: RMAN> configure channel device type disk format ‘C:\backup\sample\ora_dev_f%t_s%s_s%p’;

Describing Retention Policies
The retention policy is the determined length of time that a backup is retained for use in a potential restore, determined by configuration parameter RETENTION POLICY.

RMAN> configure retention policy to recovery window of 30 days;
i.e. backups are kept for only 30 days within the recovery catalog.

Now, lets create a backup and use TAG clause to mark this backup with a unique name called MONTHLY_BACKUP. TAG is a clause that identifies a specific name to a backup so that it can be more easily identified.
RMAN> run
{
allocate channel c1 type disk;
backup database format ‘db_%u_%d_%s’ tag monthly_backup;
backup format ‘log_t%t_s%s_p%p’
(archivelog all);
}

Next, you can modify or change this backup so that the backup will not be kept until the end of retention policy. Following statement will cause a backup to expire so that it is not protected by retention policy:
RMAN> change backupset tag monthly_backup nokeep;

Next, you can modify or change the backup to block the 30day retention policy you just had expire. The following statement blocks or excludes this backup from expiring in 30 days, which is the existing retention policy. You will set this backup to be kept until 01-DEC-08 by using the KEEP UNTIL TIME clause.
RMAN> change backupset tag monthly_backup keep until time ’01-DEC-08’ logs;

Configuring Control File Autobackup
RMAN can be configured to automatically backup the control file and other server parameter files whenever information impacting the control file is changed or modified. This is a valuable asset to a backup because this allows RMAN to recover the database even if a control file or server parameter file is lost. This process is called control file autobackup.
RMAN> configure controlfile autobackup on;

You can also configure the format of the autobackup of control file.
RMAN> configure controlfile autobackup format for device type disk to ‘C:\oracle\staging\sample\cf_%F’;

NOTE:

• Password file backups are not supported with RMAN
• CONTROL_FILE_RECORD_KEEP_TIME determines the capacity of RMAN repository