In most cases, the easiest method of duplexing backup sets is to use BACKUP... COPIES or CONFIGURE ... BACKUP COPIES to duplex backup sets. RMAN can duplex backups to either disk or tape, but cannot duplex backups to tape and disk simultaneously. https://docs.oracle.com/en/database/oracle/oracle-database/18/bradv/configuring-rman-client- advanced.html#GUID-2A285F87-552A-4F36-A5B9-F25A69611B4B