BACKUP DATABASE PLUS ARCHIVELOG;
DELETE NOPROMPT OBSOLETE.
As you already know, if a tablespace is put in BEGIN BACKUP mode then all subsequent changes will force the dirty blocks to be written into the redologs which will be eventually archived. My main concern here was regarding the DELETE OBSOLETE command. Is RMAN smart enough to know that those archives are not going to become obsolete as long as the BEGIN BACKUP status is in place? After some tests I can conclude: RMAN knows this and will NOT consider those archives as obsolete. This was kind of obvious but, you know... it's always good to try and to see by your own eyes.