RMAN Backup Optimization
RMAN Backup Optimization From 11G R1 onwards only undo data blocks containing undo data for not yet committed --- or rolled back --- transactions are backed up. Undo data in the undo tablespace still required to satisfy the undo retention but only containing undo records for already committed transactions are not backed up anymore. Nice if you have undo tablespaces of multiple Gb !!! If backup optimization is configured ( see below ) then 1. Data files belonging to read only tablespaces are not backed up all the time. It is not needed anymore to use the SKIP READONLY clause. ( Note that the SKIP READONLY could not be used for RMAN backups of standby databases. ) 2. Data files belonging to tablespaces which were offlined normal are not backed up all the time. It is not needed anymore to use the SKIP TABLESPACE clause. 3. The archivelog sequence is not backed up all the time. This is nice if you keep a large amount of archived redo logs on disk for whatever reason ( Log...