Backup of a Container Database (CDB) and a Pluggable Database (PDB) in Oracle Database 12c

Backup of a Container Database (CDB) and a Pluggable Database (PDB) in Oracle Database 12c

1. Container Database (CDB) Backup

Backup of a Container Database (CDB) is essentially the same as a non-Container Database. The main thing to remember is, by doing a full backup of the CDB you are also doing a full backup of all PDBs.

Connect to RMAN using OS authentication and take a full backup using the following command. This means you are connecting to the root container with "AS SYSDBA" privilege.

$ rman target=/

RMAN> BACKUP DATABASE PLUS ARCHIVELOG;

Note:

The datafiles associated with the CBD (cdb1) and all the PDBs (pdb1, pdb2, pdb$seed) are included in the backup.

2. Root Container Backup

A backup of the root container is a backup of the CDB, excluding any of the PDBs.

Connect to RMAN using OS authentication and backup the root container using the following command. This means you are connecting to the root container with "AS SYSDBA" privilege.

$ rman target=/

RMAN> BACKUP DATABASE ROOT;

Note:

The datafiles associated with the CBD (cdb1) are included, but all the PDBs (pdb1, pdb2, pdb$seed) are not included in the backup.

3. Pluggable Database (PDB) Backup

There are two ways to back up pluggable databases. When connected to RMAN as the root container, you can backup one or more PDBs using the following command.

$ rman target=/

RMAN> BACKUP PLUGGABLE DATABASE pdb1, pdb2;

Note:
You can see this includes the datafiles for both referenced PDBs.

Alternatively, connect to a specific PDB and issue the following command.

$ rman target=sys@pdb1

RMAN> BACKUP DATABASE;

4. Tablespace and Datafile Backups

Multiple PDBs in the same CDB can have a tablespace with the same name, for example SYSTEM, SYSAUX and USERS. One way to remove that ambiguity is connect to the appropriate PDB. Once RMAN is connected to the PDB, the tablespace backup commands is unchanged compared to previous versions.

$ rman target=sys@pdb1

RMAN> BACKUP TABLESPACE system, sysaux, users;
Alternatively, you can remove the ambiguity by qualifying the PDB name with the tablespace name when connected to the root container.

$ rman target=sys@cdb1

RMAN> BACKUP TABLESPACE pdb1:system, pdb1:sysaux, pdb1:users, pdb2:system;
Datafiles have unique file numbers and fully qualified names, so they can be backed up from the root container or the individual PDB.

$ rman target=/

# Or

$ rman target=sys@pdb1

RMAN> BACKUP DATAFILE 8, 9, 10;
If you are connecting to a PDB, only the files belonging to that PDB can be backed up. So for example, when connected as PDB1, we get an error if we try to backup the SYSTEM datafile from the root container.

RMAN> BACKUP DATAFILE 1;

Starting backup at 23-DEC-13
using channel ORA_DISK_1
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============