Which three are true about using RMAN in a Data Guard environment? 

Answer options:

A. A recovery catalog is required when RMAN is used to take backups from a logical standby database in a Data Guard configuration if you plan to recover the primary using those backups.
B. Backups of archived redo logs taken on a physical standby are interchangeable with a primary.
C. A recovery catalog is required when RMAN is used to take backups from a physical standby database if you plan to recover the primary using those backups.
D. Backups of control files taken on a physical standby are not interchangeable with a primary.
E. Backups of data files taken on a physical standby are interchangeable with a primary.

BCE

RMAN uses a recovery catalog to track filenames for all database files in a Data Guard environment. A recovery catalog is a database schema used by RMAN to store metadata about one or more Oracle databases. The catalog also records where the online redo logs, standby redo logs, tempfiles, archived redo logs, backup sets, and image copies are created. RMAN commands use the recovery catalog metadata to behave transparently across different physical databases in the Data Guard environment. For example, you can back up a tablespace on a physical standby database and restore and recover it on the primary database. Similarly, you can back up a tablespace on a primary database and restore and recover it on a physical standby database. Incorrect Answers: A: Because a logical standby database is not a block-for-block copy of the primary database, you cannot use a logical standby database to back up the primary database D: Backups of standby control files and nonstandby control files are interchangeable. For example, you can restore a standby control file on a primary database and a primary control file on a physical standby database. This interchangeability means that you can offload control file backups to one database in a Data Guard environment. RMAN automatically updates the filenames for database files during restore and recovery at the databases. References: https://docs.oracle.com/cd/E11882_01/server.112/e41134/rman.htm#SBYDB4853