You might need to backup an individual tablespace in a database that is too large to backup all at once; creating a tablespace backup at frequent intervals will reduce the amount of redo that would need to be applied to an older backup of the tablespace in the event of media failure.
You can backup one or more tablespaces with the BACKUP TABLESPACE command. The database can be mounted or open. Tablespaces can be read/write or read-only.
You need to backup the tablespace along with the control file because it contains the definition for the new tablespace. RMAN automatically backs up the control file and the server parameter file (if the instance was started with a server parameter file) when datafile 1 is included in the backup.
If control file autobackup is enabled, then RMAN writes the current control file and server parameter file to a separate autobackup piece. Otherwise, RMAN includes these files in the backup set that contains datafile 1.
The following example backs up the tools tablespaces to disk:
#Connect to RMAN
#Connect RMAN to target database
CONNECT TARGET SYS/pass@TEST1;
#Connect RMAN to recovery catalog (optional)
CONNECT CATALOG rman/cat@devdb;
#Issue RMAN BACKUP TABLESPACE command.
BACKUP AS BACKUPSET
The following example backs up the users and tools tablespaces to tape:
DEVICE TYPE sbt
TABLESPACE users, tools;