According to Oracle Backup and Recovery documentation, restoring a Pluggable Database (PDB) normally requires access to the backup of the Container Database (CDB) that originally hosted the PDB. Without the source CDB metadata, restoring a standalone PDB backup is generally not possible.
However, there is an alternative approach that can sometimes be used to recover a PDB backup and plug it into a different CDB. Although this method is not guaranteed to work in every scenario, it is a useful technique to be aware of when designing backup and recovery strategies.
In this example, we will back up a PDB named RMANPDB, transfer the backup to another server, and restore it into a completely new CDB.
Backing Up the PDB
First, verify that the PDB exists and is open:
Connected to:
Oracle Database 21c Enterprise Edition Release 21.0.0.0.0 - Production
Version 21.3.0.0.0
SQL> show pdbs
CON_ID CON_NAME OPEN MODE RESTRICTED
---------- ------------------------------ ---------- ----------
2 PDB$SEED READ ONLY NO
5 PDB1 READ WRITE NO
4 RMANPDB READ WRITE NO
Create a RMAN backup of the PDB and include the current control file:
RMAN> backup pluggable database RmanPDB format '/oracle21c/bkp_pdb/%U' current controlfile format '/oracle21c/bkp_pdb/control0000.bkp';
Starting backup at 16-OCT-21
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=266 device type=DISK
channel ORA_DISK_1: starting full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00068 name=/oracle21c/base/oradata/DB21C/CE75C2880CCD2A3FE0530488200A29C8/datafile/o1_mf_sysaux_jpo62lhz_.dbf
input datafile file number=00067 name=/oracle21c/base/oradata/DB21C/CE75C2880CCD2A3FE0530488200A29C8/datafile/o1_mf_system_jpo62lhv_.dbf
input datafile file number=00069 name=/oracle21c/base/oradata/DB21C/CE75C2880CCD2A3FE0530488200A29C8/datafile/o1_mf_undotbs1_jpo62lj1_.dbf
input datafile file number=00070 name=/oracle21c/base/oradata/DB21C/CE75C2880CCD2A3FE0530488200A29C8/datafile/o1_mf_tbs01_jpo66vjx_.dbf
channel ORA_DISK_1: starting piece 1 at 16-OCT-21
channel ORA_DISK_1: finished piece 1 at 16-OCT-21
piece handle=/oracle21c/bkp_pdb/4p0bo4mu_153_1_1 tag=TAG20211016T052342 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:03
channel ORA_DISK_1: starting full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
including current control file in backup set
channel ORA_DISK_1: starting piece 1 at 16-OCT-21
channel ORA_DISK_1: finished piece 1 at 16-OCT-21
piece handle=/oracle21c/bkp_pdb/control0000.bkp tag=TAG20211016T052342 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:01
Finished backup at 16-OCT-21
Transferring the Backup
Copy the backup pieces to the target server:
[oracle@RAC2 ~]$ mkdir -p /oracle21c/bkp_pdb
[oracle@oLinux7 ~]$ scp /oracle21c/bkp_pdb/* 192.168.1.20:/oracle21c/bkp_pdb/
4p0bo4mu_153_1_1 100% 518MB 68.8MB/s 00:07
control0000.bkp 100% 30MB 81.1MB/s 00:00
Creating a Minimal Instance
On the destination server, create a minimal initialization parameter file:
[oracle@RAC2 ~]$ vi p_1400_07_24.ora
*.db_name=db21c
*.db_create_file_dest='/oracle21c/recoverdb'
Start the instance in NOMOUNT mode:
SQL> startup nomount pfile='/home/oracle/p_1400_07_24.ora';
Restoring the Control File
Restore the control file from the backup:
RMAN> restore controlfile from '/oracle21c/bkp_pdb/control0000.bkp';
Starting restore at 16-OCT-21
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=4262 device type=DISK
channel ORA_DISK_1: restoring control file
channel ORA_DISK_1: restore complete, elapsed time: 00:00:01
output file name=/oracle21c/recoverdb/DB21C/controlfile/o1_mf_jpo703jv_.ctl
Finished restore at 16-OCT-21
Mount the database:
RMAN> alter database mount;
released channel: ORA_DISK_1
Statement processed
At this point, the metadata required to locate the PDB backup is available.
Restoring the PDB
Restore the PDB datafiles:
RMAN> RESTORE PLUGGABLE DATABASE RMANPDB;
Starting restore at 16-OCT-21
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=571 device type=DISK
channel ORA_DISK_1: starting datafile backup set restore
channel ORA_DISK_1: specifying datafile(s) to restore from backup set
channel ORA_DISK_1: restoring datafile 00067 to /oracle21c/base/oradata/DB21C/CE75C2880CCD2A3FE0530488200A29C8/datafile/o1_mf_system_jpo62lhv_.dbf
channel ORA_DISK_1: restoring datafile 00068 to /oracle21c/base/oradata/DB21C/CE75C2880CCD2A3FE0530488200A29C8/datafile/o1_mf_sysaux_jpo62lhz_.dbf
channel ORA_DISK_1: restoring datafile 00069 to /oracle21c/base/oradata/DB21C/CE75C2880CCD2A3FE0530488200A29C8/datafile/o1_mf_undotbs1_jpo62lj1_.dbf
channel ORA_DISK_1: restoring datafile 00070 to /oracle21c/base/oradata/DB21C/CE75C2880CCD2A3FE0530488200A29C8/datafile/o1_mf_tbs01_jpo66vjx_.dbf
channel ORA_DISK_1: reading from backup piece /oracle21c/bkp_pdb/4p0bo4mu_153_1_1
channel ORA_DISK_1: piece handle=/oracle21c/bkp_pdb/4p0bo4mu_153_1_1 tag=TAG20211016T052342
channel ORA_DISK_1: restored backup piece 1
channel ORA_DISK_1: restore complete, elapsed time: 00:00:07
Finished restore at 16-OCT-21
RMAN restores all datafiles belonging to the PDB.
It is important to understand that only the datafiles have been restored. The PDB itself is not yet usable because it is not associated with an operational CDB.
Identifying the Restored Datafiles
Determine the location of the restored datafiles:
SQL> show pdbs
CON_ID CON_NAME OPEN MODE RESTRICTED
---------- ------------------------------ ---------- ----------
2 PDB$SEED MOUNTED
4 RMANPDB MOUNTED
5 PDB1 MOUNTED
SQL> select name from v$datafile where con_id=4;
/oracle21c/recoverdb/DB21C/CE75C2880CCD2A3FE0530488200A29C8/datafile/o1_mf_system_jpo72qsh_.dbf
/oracle21c/recoverdb/DB21C/CE75C2880CCD2A3FE0530488200A29C8/datafile/o1_mf_sysaux_jpo72ppx_.dbf
/oracle21c/recoverdb/DB21C/CE75C2880CCD2A3FE0530488200A29C8/datafile/o1_mf_undotbs1_jpo72s8q_.dbf
/oracle21c/recoverdb/DB21C/CE75C2880CCD2A3FE0530488200A29C8/datafile/o1_mf_tbs01_jpo72ssg_.dbf
Generating the XML
To plug the restored PDB into another CDB, an XML file must be created.
Connect to an open CDB and use the DBMS_PDB.RECOVER procedure:
[oracle@RAC2 ~]$ srvctl start database -db db21c
[oracle@RAC2 ~]$ sqlplus "/as sysdba"
SQL*Plus: Release 21.0.0.0.0 - Production on Sat Oct 16 13:23:36 2021
Version 21.3.0.0.0
BEGIN
DBMS_PDB.RECOVER (
pdb_descr_file => '/home/oracle/RMANPDB.xml',
pdb_name => 'RMANPDB',
filenames => '
/oracle21c/recoverdb/DB21C/CE75C2880CCD2A3FE0530488200A29C8/datafile/o1_mf_system_jpo72qsh_.dbf,
/oracle21c/recoverdb/DB21C/CE75C2880CCD2A3FE0530488200A29C8/datafile/o1_mf_sysaux_jpo72ppx_.dbf,
/oracle21c/recoverdb/DB21C/CE75C2880CCD2A3FE0530488200A29C8/datafile/o1_mf_undotbs1_jpo72s8q_.dbf,
/oracle21c/recoverdb/DB21C/CE75C2880CCD2A3FE0530488200A29C8/datafile/o1_mf_tbs01_jpo72ssg_.dbf
'
);
END;
/
PL/SQL procedure successfully completed.
The procedure creates an XML manifest describing the PDB.
A portion of the generated file looks like this:
[oracle@RAC2 ~]$ less /home/oracle/RMANPDB.xml
<?xml version="1.0" encoding="UTF-8"?>
<PDB>
<xmlversion>1</xmlversion>
<pdbname>RMANPDB</pdbname>
<cid>4</cid>
<byteorder>0</byteorder>
<vsn>0</vsn>
<vsns>
<vsnnum>0.0.0.0.0</vsnnum>
<cdbcompt>0.0.0.0.0</cdbcompt>
<pdbcompt>21.0.0.0.0</pdbcompt>
<vsnlibnum>0.0.0.0.0</vsnlibnum>
<vsnsql>0</vsnsql>
<vsnbsv>0.0.0.0.0</vsnbsv>
</vsns>
<dbid>3948388369</dbid>
<ncdb2pdb>0</ncdb2pdb>
<cdbid>246486353</cdbid>
<guid>CE75C2880CCD2A3FE0530488200A29C8</guid>
Plugging the PDB into a New CDB
Create the PDB using the XML :
SQL> CREATE PLUGGABLE DATABASE RMANPDB USING '/home/oracle/RMANPDB.xml' NOCOPY;
Pluggable database created.
Verify that the PDB has been created:
SQL> show pdbs
CON_ID CON_NAME OPEN MODE RESTRICTED
---------- ------------------------------ ---------- ----------
2 PDB$SEED READ ONLY NO
3 PDB1 READ WRITE NO
4 PDB2 READ WRITE NO
5 RMANPDB MOUNTED
Opening the PDB
The PDB may initially open in migration mode and generate warnings.
SQL> ALTER DATABASE UPGRADE SYNC OFF;
Database altered.
SQL> alter pluggable database RMANPDB open ;
Warning: PDB altered with errors.
SQL> show pdbs
CON_ID CON_NAME OPEN MODE RESTRICTED
---------- ------------------------------ ---------- ----------
2 PDB$SEED READ ONLY NO
3 PDB1 READ WRITE NO
4 PDB2 READ WRITE NO
5 RMANPDB READ WRITE YES
Validating the Recovery
Connect to the restored PDB and verify that application objects are accessible:
[oracle@RAC2 ~]$ sqlplus "usef/a@192.168.1.20:1521/RMANPDB"
Oracle Database 21c Enterprise Edition Release 21.0.0.0.0 - Production
Version 21.3.0.0.0
SQL> select count(*) from usef.tbl1;
COUNT(*)
----------
91
SQL> create table usef.tbl2 as select * from tbl1;
Table created.
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