Relocated PDBs in Oracle Database 18c

Oracle 18c allows RMAN backups created before the non-CDB or PDB was migrated into a different target CDB can be used for recovery operations. The COMPATIBLE parameter of the source and Oracle Cloud must be set to 18.0.0 or higher

The RMAN commands used to backup and recovery CDBs and PDBs are the same as those used for non-CDBs, with few variations in the syntax.

The backup and recovery operations performed on non-CDBs can also be performed on CDBs and PDBs. This includes the following:
– Full and incremental backups
– Complete and point-in-time recovery (PITR)
– Reporting operations (such as listing and cross-checking backups)
– Flashback Database

We need take metadata for the existing backups and available to the destination CDB. To export metadata user needs to run DBMS_PDB.EXPORTRMANBACKUP procedure on the source database.

EXECUTE DBMS_PDB.exportrmanbackup();
Or
EXECUTE DBMS_PDB.exportrmanbackup('EMP_PDB');

In case if you are unplug you no need to run this command as unplug already includes the metadata.

Convert NON-CDB to PDB : As we have metadata, now we can covert the NON-CDB instance to PDB.

Step1: Open the non-CDB instance in read-only mode and describe and shutdown

SQL> SHUTDOWN IMMEDIATE;
SQL> STARTUP OPEN READ ONLY;
SQL> BEGIN
DBMS_PDB.DESCRIBE( pdb_descr_file => '/oracle/empdb.xml');
END;
SQL> SHUTDOWN IMMEDIATE;

Step2: Create the new pluggable database using the non-CDB description file that we have taken in above step

SQL> CREATE PLUGGABLE DATABASE empdb_pdb USING '/oracle/empdb.xml' COPY;
SQL> ALTER SESSION SET CONTAINER= empdb_pdb;
SQL> @$ORACLE_HOME/rdbms/admin/noncdb_to_pdb.sql
SQL> ALTER PLUGGABLE DATABASE OPEN;
SQL> ALTER PLUGGABLE DATABASE SAVE STATE;

Step3:- Restore and recovery using pre-plugin backup

SQL> ALTER PLUGGABLE DATABASE empdb_pdb CLOSE IMMEDIATE;

RMAN> SET PREPLUGIN CONTAINER=db18cpdb;

RMAN> RESTORE PLUGGABLE DATABASE empdb_pdb FROM PREPLUGIN;
RMAN> RECOVER PLUGGABLE DATABASE empdb_pdb FROM PREPLUGIN;

Sometimes users may come across RMAN-06054 error in that case you need to CATALOG the missing archive log and start the recovery again.

RMAN-06054: media recovery requesting unknown archived log for thread 3 sequence 94983
RMAN>SET PREPLUGIN CONTAINER= empdb_pdb;
RMAN>CATALOG PREPLUGIN ARCHIVELOG 'oracle/archivelog/arc_empdb_pdb_3_94983.arc';
RMAN>RECOVER PLUGGABLE DATABASE empdb_pdb FROM PREPLUGIN;

Perform normal recovery and open the database

RMAN>RECOVER PLUGGABLE DATABASE empdb_pdb;
RMAN>ALTER PLUGGABLE DATABASE empdb_pdb OPEN;


Reference:
Check preplugin backups available to the CDB instance
RMAN> LIST PREPLUGIN BACKUP OF PLUGGABLE DATABASE empdb_pdb;

Preplugin backups are usable only on the destination CDB into which you plug in the source non-CDB or PDB

Regards

Satishbabu Gunukula, Oracle ACE

http://www.oracleracexpert.com