1. Introduction
Oracle Multitenant
architecture allows a Container Database (CDB) to host multiple Pluggable
Databases (PDBs). In real-world production environments, failures often
impact only a single PDB rather than the entire CDB.
This document explains
how to restore and recover a single PDB from a full CDB RMAN backup in Oracle
Database 19c, covering both storage scenarios:
- Restore on NFS (File System)
- Restore on ASM (Automatic Storage
Management)
The same RMAN backup is
reused; only the storage configuration differs.
2. Objective
- Take
a full RMAN backup of the CDB
- Restore
only one PDB (TESTPDB) from that backup
- Perform
restore on:
- NFS-based
storage
- ASM-based
storage
- Avoid
restoring the complete CDB
- Validate
successful recovery
3. Environment Overview
Scenario 1: Source on NFS → Target on NFS
Source Environment (NFS-Based)
- Database
Type: Container Database (CDB)
- Source
CDB Name: ORCL
- Oracle
Version: Oracle Database 19c (19.3)
- Storage
Type: NFS / File System
- Database
Mode: ARCHIVELOG
- Backup
Tool: RMAN
Pluggable Databases in Source CDB
- ORCLPDB
- QAPDB
- FINPDB
- SECPDB
- TESTPDB
Backup Details
- Backup
Type: Full CDB RMAN Backup
- Backup
Includes:
- CDB
root datafiles
- All
PDB datafiles
- Archived
redo logs
- Control
file
- SPFILE
Target Environment (NFS-Based)
- Target
Host: Separate server
- Target
CDB Name: ORCL
- Oracle
Version: 19.3
- Storage
Type: NFS / File System
- Datafile
Location: /u02/oradata/ORCL
- FRA
Location: /u02/fra/ORCL
- Restore
Scope: Only TESTPDB
Goal (Scenario 1)
To restore only TESTPDB on a target NFS-based CDB,
using a full RMAN backup taken from a source NFS-based CDB (ORCL), without
restoring other PDBs or the entire CDB.
Scenario 2: Source on ASM → Target on ASM
Source Environment (ASM-Based)
- Database
Type: Container Database (CDB)
- Source
CDB Name: PROD
- Oracle
Version: Oracle Database 19c (19.3)
- Storage
Type: ASM
- ASM
Disk Groups:
- +DATA
→ Datafiles
- +RECO
→ Archivelogs and FRA
- Database
Mode: ARCHIVELOG
- Backup
Tool: RMAN
Pluggable Databases in Source CDB
- PRODPDB
- APPPDB
- DEVPDB
- TESTPDB
Backup Details
- Backup
Type: Full CDB RMAN Backup
- Backup
Includes:
- CDB
root datafiles
- All
PDB datafiles
- Archived
redo logs
- Control
file
- SPFILE
Target Environment (ASM-Based)
- Target
Host: Separate server
- Target
CDB Name: PROD
(Kept same as source for clarity; can be renamed if required) - Oracle
Version: 19.3
- Storage
Type: ASM
- ASM
Disk Groups:
- +DATA
→ Datafiles
- +RECO
→ FRA and Archivelogs
- Restore
Scope: Only TESTPDB
Goal (Scenario 2)
To restore only TESTPDB on a target ASM-based CDB,
using a full RMAN backup taken from an ASM-based source CDB (PROD), without
restoring or impacting other PDBs.
4. Prerequisites
- Compatible
Oracle versions on source and target
- Full
RMAN backup available:
- Database
- Archivelogs
- Controlfile
- SPFILE
- Password
file copied to target
- PFILE
available
- Adequate
storage space
- Correct
ORACLE_HOME and ORACLE_SID
- Backup
pieces copied to target server
5. High-Level Architecture
Flow
1.
Validate source database status
2.
Take full RMAN backup of CDB
3.
Copy backup pieces and configuration files
to target
4.
Prepare target environment
5.
Restore control file and mount database
6.
Catalog backups
7.
Restore and recover only TESTPDB
8.
Open restored PDB and validate
6. Implementation – Restore
on NFS (File System)
6.1: Source Database Prechecks and Full
Backup
This section describes the source-side validation and
backup preparation before restoring a single PDB (TESTPDB) on the target
system.
6.1.1 Source Database Basic Information
6.1.2 Verify Archive Log Configuration
6.1.3 Verify Container and PDB Information
6.1.4 Verify Datafile Locations &
ControlFile Locations (NFS)
6.1.5 Capture DBID (Mandatory for Recovery
Safety)
6.1.6 RMAN Backup Directory Verification
6.1.7 Full CDB RMAN Backup (NFS)
A full CDB backup is taken, including:
- All
CDB and PDB datafiles
- Archived
redo logs
- Control
file
- SPFILE
6.2 Copy Backup and Configuration from
Source to Target
This step covers copying RMAN backup pieces and
database configuration files from the source host (srv5) to the
target host (srv7).
6.2.1 Target Directory Structure Creation
(srv7)
On the target host (srv7), create the directory
structure.
The layout mirrors the source NFS structure for consistency.
6.2.2 Copy RMAN Backup Pieces from Source
(srv5)
Navigate to the RMAN backup directory on the source
host.
6.2.3 Copy
Password File (SYSDBA Authentication)
6.2.4
Create and Copy PFILE (Optional but Recommended)
6.3 Target Host OS and Environment
Preparation
6.3.1 Verify Backup Transfer on Target
(srv7)
6.3.2 Verify Configuration Files on Target
6.3.3 Set Oracle Environment on Target
6.4 Create Minimal Initialization File on
Target
A minimal init.ora is required to start the instance
in NOMOUNT mode.
6.5 Start Instance in NOMOUNT and Restore
Control File (NFS)
This step initializes the target database instance in
NOMOUNT mode and restores the control file from the RMAN backup copied from the
source system.
6.5.1 Start Instance in NOMOUNT Mode
Connect to SQL*Plus on the target server (srv7) as
SYSDBA.
6.5.2 Connect to RMAN on Target
6.6 Catalog RMAN Backups and Inspect
Backup Metadata
After mounting the database, the copied RMAN backup
pieces must be cataloged so that RMAN can recognize and use them.
6.6.1 Catalog Backup Pieces
6.6.2 Inspect Database Schema from Control
File
6.7 Restore the Database (ROOT + PDB$SEED
+ TESTPDB)
Since the target file paths are identical to source,
there is no need to set NEWNAME. The full database (ROOT, PDB$SEED, TESTPDB,
and other PDBs) is restored.
6.8 Recover Database While Skipping
Unwanted PDBs
Since we only want TESTPDB to be recovered, other PDBs
are permanently skipped in the recovery process.
This tells RMAN:
• Recover
ROOT + PDB$SEED + TESTPDB
• Permanently
mark the other PDBs as unrecoverable
Perfect for TESTPDB‑only restore.
6.9 Open the CDB and Reset Logs
After recovery, open the CDB with RESETLOGS to
complete the recovery process.
6.9.1 Verify PDBs
6.9.2 — Drop Unwanted Pluggable Databases
(ORCLPDB, QAPDB, FINPDB, SECPDB)
6.9.3 Verify Remaining PDBs
6.9.4 Save TESTPDB Open State
6.9.5 Validate TESTPDB
✔ TESTPDB data
✔
Object counts match expected values
✔
Database is production-ready
Note:
Compare these values with pre-recovery source counts if
prechecks were captured.
7. Implementation – Restore
on ASM
ASM Disk Groups Used
- +DATA
→ Datafiles
- +RECO
→ Archivelogs and FRA
7.1: Source Database Prechecks and Full
Backup
This section describes the source-side validation and
backup preparation before restoring a single PDB (TESTPDB) on the target
system.
7.1.1 Source Database Basic Information
7.1.2 Verify Archive Log Configuration
7.1.3 Verify Container and PDB Information
7.1.4 Verify Datafile Locations &
ControlFile Locations (NFS)
7.1.5 RMAN Backup Directory Verification
Full backup to filesystem (not ASM), Pick a backup
directory, e.g. : /backup/PROD
7.1.6 Full CDB RMAN Backup (ASM)
A full CDB backup is taken, including:
- All
CDB and PDB datafiles
- Archived
redo logs
- Control
file
- SPFILE
7.2 Copy Backup and Configuration from
Source to Target
This step covers copying RMAN backup pieces and
database configuration files from the source host (srv5) to the
target host (srv7).
7.2.1 Target Directory Structure Creation
(srv7)
On the target host (srv7), create the directory
structure.
The layout mirrors the source ASM structure for consistency.
7.2.2 Copy RMAN Backup Pieces from Source
(srv5)
Navigate to the RMAN backup directory on the source
host.
7.2.3 Copy
Password File (SYSDBA Authentication)
7.2.4
Create and Copy PFILE (Optional but Recommended
7.3 Target Host OS and Environment
Preparation
7.3.1 Set Oracle Environment on Target
7.3.2 Create Minimal Initialization File
on Target
A minimal init.ora is required to start the instance
in NOMOUNT mode.
7.4 Start Instance in NOMOUNT and Restore
Control File
This step initializes the target database instance in
NOMOUNT mode and restores the control file from the RMAN backup copied from the
source system.
7.4.1 Start Instance in NOMOUNT Mode
Connect to SQL*Plus on the target server (srv7) as
SYSDBA.
7.4.2 Connect to RMAN on Target
7.5 Catalog RMAN Backups and Inspect
Backup Metadata
After mounting the database, the copied RMAN backup
pieces must be cataloged so that RMAN can recognize and use them.
7.5.1 Catalog Backup Pieces
7.5.2 Inspect Database Schema from Control
File
7.6 Restore the Database (ROOT + PDB$SEED
+ TESTPDB)
Since the target file paths are identical to source,
there is no need to set NEWNAME. The full database (ROOT, PDB$SEED, TESTPDB,
and other PDBs) is restored.
7.7 Recover Database While Skipping
Unwanted PDBs
Since we only want TESTPDB to be recovered, other PDBs
are permanently skipped in the recovery process.
This tells RMAN:
• Recover
ROOT + PDB$SEED + TESTPDB
• Permanently
mark the other PDBs as unrecoverable
Perfect for TESTPDB‑only restore.
7.8 Open the CDB and Reset Logs
After recovery, open the CDB with RESETLOGS to
complete the recovery process.
7.8.1 Verify PDBs
7.8.2 — Drop Unwanted Pluggable Databases
(PRODPDB, APPDB, DEVPDB)
7.8.3 Verify Remaining PDBs
7.8.4 Save TESTPDB Open State
7.8.5 Validate TESTPDB
Note:
Compare these values with pre-recovery source counts if
prechecks were captured.
8. Key Differences: NFS vs
ASM
|
Aspect |
NFS |
ASM |
|
File Management |
Manual paths |
Oracle managed |
|
Performance |
Moderate |
High |
|
Scalability |
Limited |
Highly scalable |
|
Production Usage |
Small/Medium |
Enterprise |
9. Conclusion
This document demonstrates a real production-level
Oracle DBA recovery scenario, where a single PDB is restored from a full
CDB RMAN backup on both:
- NFS-based
storage
- ASM-based
storage
Using the same backup strategy, Oracle RMAN provides flexibility,
reliability, and granular recovery, making it ideal for multitenant
environments.
This approach is widely used for:
- PDB-level
corruption recovery
- User
error rollback
- Test
and migration activities
- Disaster
recovery scenarios