Configuring and Backing Up Oracle Databases Using RMAN - OCP: Oracle Database 12c Administrator Certified Professional - page 124

■ Another full database backup 2 is taken on day 16. Database backup 1 is still valid.
Why? Because you need database backup #1 to restore the database to day 10, or day 9,
since database backup 2 is valid for only day 16 and beyond.
■ Archive log backups are taken on days 17 through 29. Day 29 would be the 14 th day
since backup 2 was taken.
■ On day 29, backup 1 and all the associated archived redo logs are finally eligible
for removal.
When the backup is marked obsolete, it is eligible for removal. If it exists in the FRA,
then Oracle will remove it automatically (usually when more space is required). If it is not in
the FRA, you can use the LIST OBSOLETE command to list those backups subject to removal
based on the retention policy and then use the DELETE OBSOLETE command to remove those
backups. Here is an example:
RMAN> report obsolete;
RMAN retention policy will be applied to the command
RMAN retention policy is set to redundancy 2
Report of obsolete backups and copies
Type Key Completion Time Filename/Handle
-------------------- ----- --------------- --------------------
Backup Set 19 05-SEP-
Backup Piece 36 05-SEP-14 C:\ORACLE\BACKUP\0MJPS3LL_3_1.ORCL
Backup Set 19 05-SEP-14
Backup Piece 35 05-SEP-14 C:\ORACLE\BACKUP\0MJPS3LL_2_1.ORCL
Backup Set 19 05-SEP-14
Backup Piece 34 05-SEP-14 C:\ORACLE\BACKUP\0MJPS3LL_1_1.ORCL
Backup Set 20 05-SEP-14
Backup Piece 37 05-SEP-14 C:\ORACLE\BACKUP\0NJPS3VG_1_1.ORCL
Backup Set 21 05-SEP-14
Backup Piece 38 05-SEP-14 C:\ORACLE\BACKUP\0OJPS402_1_1.ORCL
Backup Set 22 07-SEP-14
Backup Piece 39 07-SEP-14 C:\ORACLE\FAST_RECOVERY_AREA\ORCL
\BACKUP SET\2013_09_07\O1_MF_ANNNN_TAG20080907T170612_4D8QMNYR_.BKP
RMAN> delete noprompt obsolete;
RMAN retention policy will be applied to the command
RMAN retention policy is set to redundancy 2
using channel ORA_DISK_1
Deleting the following obsolete backups and copies:
Type Key Completion Time Filename/Handle
-------------------- ----- --------------- --------------------
Backup Set 19 05-SEP-14
Backup Piece 36 05-SEP-14 C:\ORACLE\BACKUP\0MJPS3LL_3_1.ORCL
Backup Set 19 05-SEP-14
Backup Piece 35 05-SEP-14 C:\ORACLE\BACKUP\0MJPS3LL_2_1.ORCL