About Creating Transportable Tablespace Sets from Backup with RMAN

The method of creating transportable tablespace sets described in Oracle Database Administrator's Guide requires that the tablespaces to be transported are opened read-only for the duration of the tablespace transport process.

By contrast, when RMAN creates transportable tablespace sets from backup, it does not need access to the live datafiles from the tablespaces to be transported. This eliminates the need to put the tablespace in read-only mode. As a result, database availability is improved, especially for large tablespaces, because the tablespaces to be transported can remain open for writes during the process, and because putting a tablespace into read-only mode can take a long time, depending upon current database activity.

Using RMAN for creating a transportable tablespace set also enables you to specify a target point in time, SCN or restore point during your recovery window and transport the data as it stood at that time rather than as it stands at the time of the TRANSPORT TABLESPACE. If, for example, your backup retention policy guarantees a one week recovery window, and you want to create transportable tablespaces for reporting based upon the contents of your database on the last day of the month, you can use RMAN to do so at any time during the first week of the next month.

The RMAN TRANSPORT TABLESPACE command is used to create transportable tablespace sets from RMAN backups.