If limited disk space is available, or a backup across a network environment imposes bandwidth restrictions, or if the backup is to be transported on media with a limited storage capacity, then a compressed backup is a good option.
The compressed backup can be directly configured as an option for the CONFIGURE CHANNEL command.
CONFIGURE DEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO COMPRESSED BACKUPSET;
Once the backup is performed, it will be done in a compressed format.
The compression can also be configured in a non-persistent way, it can be specified directly as a command option:
BACKUP AS COMPRESSED BACKUPSET DATABASE PLUS ARCHIVELOG;
In order for the DBA to recover from a compressed backup, they just need to issue the regular RESTORE/RECOVER commands. There are no specific parameters required to recover from a compressed backup set.
Let's take a look at the backup with compression enabled:
RMAN> BACKUP AS COMPRESSED BACKUPSET DATABASE PLUS...