Rman backup level 0 and then cumulative

Question

Hi All,
I have a system that had a level 0 backup done last year and since then the following has taken place
run {
allocate channel oem_disk_backup device type disk;
recover copy of database with tag 'ORA\$OEM_LEVEL_0';
backup incremental level 1 cumulative copies=1 for recover of copy with tag 'ORA\$OEM_LEVEL_0' database;
In the event of recovery, how will RMAN handle this. I am sure that the orignal level 0 is not now on disk.
best regards
Alan

Answer 1

This is an incrementally updated backup. The first time the scripts runs, recover copy ... does nothing and backup incremental level 1 ... creates image copies (not a backupset) of the datafiles. That can be seen as level 0 base backup and you should still have these image copies,
The second time, recover copy ... again does anything (because no incremental backup exists at this time), but backup incremental level 1 ... now creates its first incremental backup.
From now on (third,fourth and so on time) the process does always the same:
recover copy ... applies the incremental backup previously created to the image copies,
backup incremental level 1 ... performs the next incremental backup.
That seems to be the 'Oracle suggested' backup script generated by EM. Archivelogs should be backed up, too.
Werner