RMAN-08138: WARNING: archived log not deleted - must create more backups

When I take the RMAN backup to disk of 12c Oracle database, seeing the error "RMAN-08138: WARNING: archived log not deleted - must create more backups" and archive logs are not getting deleted after the backup.

That is, rman is able to take the backup of database and archive logs but not deleting the backed up archive logs in order to free up the space.

Solution:-

The problem was with the below default configuration setting, as per this RMAN is looking to delete the archive logs that are backed up to SBT_TAPE.

CONFIGURE ARCHIVELOG DELETION POLICY TO BACKED UP 1 TIMES TO 'SBT_TAPE';

But as I said I am taking the backup to Disk, I changed the configuration parameter as below  to delete the archive logs after backing up to Disk.

CONFIGURE ARCHIVELOG DELETION POLICY TO BACKED UP 1 TIMES TO DISK;

Now rman is able to delete the archive logs after the backup to disk.