1. Administering Oracle Database Exadata Cloud at Customer (Gen 1/OCI-C)
  2. Migrating Oracle Databases to Exadata Cloud at Customer
  3. Migration Methods
  4. Cloning a Remote PDB or Non-CDB

Cloning a Remote PDB or Non-CDB

You can use this method only if the source platform is little endian, and the database character set is AL32UTF8 or a compatible subset. It uses the multitenant architecture in Oracle Database 12c, or later, in conjunction with a database link to clone the source database directly over the network. The process is simple; however, it may not be feasible for large databases or situations involving slow or unreliable network links.

Cloning a Remote PDB or Non-CDB is very similar to unplugging and plugging in a PDB or plugging in a Non-CDB. The major difference is that remote cloning uses a database link to transfer the data as part of running the CREATE PLUGGABLE DATABASE command. As a result, remote cloning is even simpler than preparing, transporting and plugging in a PDB. However, since remote cloning depends on transporting the data over a database link, you must consider the size of your source database and the speed of your Internet connection in order to determine whether it is a feasible migration approach in your case.

Cloning a Remote PDB or Non-CDB has similar requirements and restrictions compared with unplugging and plugging in a PDB or plugging in a Non-CDB:

  • The source database must be version is 12.1 or later.

  • The source and target platform must have the same endian format, which is little-endian for Exadata Cloud at Customer.

  • Ideally, the source and target CDBs must use the same character set, which is AL32UTF8 for Exadata Cloud at Customer. Alternatively, the PDB character set must by a multibyte character set that is a binary subset of AL32UTF8, such as UTF8 for example; however, complications may arise if the different character sets have different maximum character widths.

Furthermore, if you are creating a PDB by cloning a non-CDB, then both the target CDB and the source non-CDB must be running Oracle Database 12c version 12.1.0.2, or later.

To migrate a PDB or Non-CDB to Exadata Cloud at Customer using the remote cloning method, you perform these tasks:

  1. Place the source PDB or Non-CDB in read-only mode.

  2. On the target CDB, create a database link that enables a connection to the source database.

  3. On the target CDB, run the CREATE PLUGGABLE DATABASE statement and specify the source PDB or the source non-CDB in the FROM clause.

    For example, assuming that you have a database link to a source PDB or Non-CDB named mylink and the name of your source database is mydb, then the following statement creates a cloned PDB named newpdb: 

    SQL> CREATE PLUGGABLE DATABASE newpdb FROM mydb@mylink;

  4. If your source is a non-CDB, connect to the target PDB as a SYSDBA user and execute the $ORACLE_HOME/rdbms/admin/noncdb_to_pdb.sql script to delete unnecessary metadata from the SYSTEM tablespace of the new PDB.

  5. Open the target PDB in read-write mode by executing the ALTER PLUGGABLE DATABASE ... OPEN READ WRITE command.

See Cloning a Remote PDB or Non-CDB in Oracle Database Administrator's Guide for Release 18, 12.2, or 12.1.