Oracle Multitenant Architecture allows organizations to run multiple pluggable databases (PDBs) within a single container database (CDB). As databases grow and environments change, migrating PDBs becomes essential—whether for resource optimization , version upgrades , moving to cloud , or consolidation . This blog explains all major PDB migration techniques , when to use them, step-by-step workflows, benefits, limitations, and real-world use cases.

PDB migration is common in:

Moving PDBs between on-prem servers or cloud.

Shifting PDBs to new servers with better CPU, RAM, or storage.

Migrating PDBs to a new version of the CDB.

Distributing PDBs across multiple CDBs to avoid performance bottlenecks.

Cloning or migrating PDBs to other environments.

Below are the most common and recommended techniques for Oracle DBAs:

This is the most traditional migration method, used when moving a PDB between CDBs with the same version .

- Close the PDB: Close the PDB: - Unplug the PDB: Unplug the PDB: - Copy datafiles to target CDB. Copy datafiles to target CDB. - Plug into new CDB: Plug into new CDB: - Run PDB compatibility check and fix violations. Run PDB compatibility check and fix violations. - Open PDB: Open PDB:

- Clean migration Clean migration - Easy validation Easy validation - Supports metadata transport Supports metadata transport

- Requires downtime Requires downtime - CDB versions must match CDB versions must match

Used to create a copy of a PDB on the same CDB.

- Quick dev/test environment creation Quick dev/test environment creation - Data masking Data masking - Zero-impact testing Zero-impact testing

Cloning a PDB from a remote CDB using a database link.

- Create DB link to source CDB. Create DB link to source CDB. - Execute: Execute: - Open with required conversions. Open with required conversions.

- Requires minimal downtime Requires minimal downtime - No need to manually transfer files No need to manually transfer files - Ideal for on-prem to cloud migration Ideal for on-prem to cloud migration

A refreshable PDB maintains incremental sync with a source PDB.

- Near-zero downtime during cutover Near-zero downtime during cutover - Best for production migrations Best for production migrations - Works for cloud onboarding (OCI) Works for cloud onboarding (OCI)

Used when only specific schemas/tablespaces need to be migrated.

- Set tablespaces READ ONLY Set tablespaces READ ONLY - Export metadata Export metadata - Transfer datafiles Transfer datafiles - Import into target CDB Import into target CDB

- Partial migrations Partial migrations - Schema-level transport Schema-level transport - Moving large datafiles efficiently Moving large datafiles efficiently

A universal migration approach, works across different Oracle versions.

- Export PDB/Schemas: Export PDB/Schemas: - Copy dump file to target server. Copy dump file to target server. - Import into target CDB/PDB: Import into target CDB/PDB:

- Version upgrade Version upgrade - Cross-platform migration Cross-platform migration - When other PDB methods fail When other PDB methods fail

- Slow for large datasets Slow for large datasets - Needs downtime Needs downtime

Oracle GoldenGate enables zero-downtime PDB migration through real-time replication.

- Configure extract on source PDB Configure extract on source PDB - Configure replicat on target PDB Configure replicat on target PDB - Sync data in near real-time Sync data in near real-time - Perform cutover Perform cutover

- Cloud migrations Cloud migrations - Active-active setups Active-active setups - High Availability High Availability

- Zero downtime: GoldenGate, Refreshable PDB Zero downtime: GoldenGate, Refreshable PDB - Low downtime: Remote Cloning Low downtime: Remote Cloning - High downtime acceptable: Unplug/Plug High downtime acceptable: Unplug/Plug

- Same version CDB: Unplug/Plug Same version CDB: Unplug/Plug - Cross-version upgrade: Data Pump Cross-version upgrade: Data Pump - Large DB: Transportable Tablespaces Large DB: Transportable Tablespaces

Use:

Yes, but not using unplug/plug. Use Data Pump or GoldenGate .

Oracle GoldenGate and Refreshable PDB provide near-zero downtime.

Yes. Both CDBs should be on the same version and patch level .

Remote cloning and transportable tablespaces are fastest for large databases.

Use transportable tablespaces or Data Pump schema-level export/import .