An other errors of one of my costumer, trying to enjoy the Oracle backup and recovery workshop, and after some steps, he has got this RMAN error:
RMAN-08138: warning: archived log not deleted - must create more backups
RMAN> SHOW ARCHIVELOG DELETION POLICY;
RMAN configuration parameters for database with db_unique_name ORCL are:
CONFIGURE ARCHIVELOG DELETION POLICY TO BACKED UP 1 TIMES TO DISK;
You cannot delete archive log files not backed up yet.