I set up RMAN full backup on Sunday and incremental accumulative backup on the rest of the week. It works perfect but after the full backups failed one day, I got problems. The problem is the incremental backups takes more space than the level 0 full backups everyday. So soon I ran out of disk space.
I missed the level 0 backup on Sunday and when the RMAN do incremental level 1 backup on Monday, it actually do a full backup. It's fine since it can not find a full backup. But on Tuesday, it do a full backup again even I already have a full backup, which is Monday's level 1 backup. On Wednsday, it do a full backup again.
I know it will not happen if we do incremental differential backup. But hell! Why RMAN can't be design smart enough to recognize the Monday's level 1 backup is actually a full backup!