If you require a certain number of backups to be retained, you can set the retention policy based on the redundancy option. This option requires that a specified number of backups be cataloged before any backup is identified as obsolete. The default retention policy has a redundancy of 1, which means that only one backup of a file must exist at any given time. A backup is deemed obsolete when a more recent version of the same file has been backed up. For example, you can use the following command to configure a redundancy recovery policy of 2:


If you want to perform a cross-platform upgrade, you need to know the restrictions and guidelines of this method.

When using DBUA or performing a manual upgrade for Oracle Database, you cannot directly migrate or transport data in a database on one operating system to another operating system. For example, you cannot migrate data in an Oracle database on Solaris to an Oracle 19c database on Windows using DBUA. You must follow procedures specific to your operating system platforms.

To see the platforms that support cross-platform data transport, run the following query using SQL*Plus:

If the source platform and the target platform are of different endianness, then you cannot use the RMAN CONVERT DATABASE  command. This process requires both the source and target platform to be the same endian value. Your available options are Data Pump replication, Data Pump export/import, or Transportable Tablespace, with an RMAN CONVERT TABLESPACE. If the platforms are of the same endianness, then no conversion is necessary and data can be transported as if on the same platform.

For more information see:

Oracle Database Administrator’s Guide for a discussion of transporting data across platforms

Oracle Database Backup and Recovery User’s Guide for information on using the RMAN CONVERT DATABASE and RMAN CONVERT TABLESPACE commands