Backup, Recovery & Data Guard Flashcards

What is a 'snapshot standby' database in Oracle Data Guard?

Answer: A standby temporarily opened read-write for testing while accumulating primary redo

A snapshot standby is converted to read-write (often using flashback) for testing; it buffers incoming redo and resynchronizes when converted back.

The RMAN command REPORT OBSOLETE identifies backups that are no longer needed. What makes a backup 'obsolete'?

Answer: The backup is no longer needed to satisfy the configured retention policy

A backup is obsolete when it is no longer required to meet the RMAN retention policy (either REDUNDANCY or RECOVERY WINDOW).

Which Oracle feature, used with Data Guard, automatically recovers the primary's lost datafiles from the standby after a failover?

Answer: Automatic Block Repair

Automatic Block Repair uses a Data Guard standby to automatically replace corrupted or lost blocks in the primary from the standby copy.

In RMAN, what is the purpose of the CATALOG RECOVERY AREA command?

Answer: Re-registers all backup files in the FRA with the RMAN repository after a catalog rebuild

CATALOG RECOVERY AREA scans the Fast Recovery Area and registers any unrecorded backup files back into the RMAN control file or catalog.

When using RMAN with a recovery catalog, what advantage does it provide over using only the control file?

Answer: Stores backup history beyond the CONTROL_FILE_RECORD_KEEP_TIME limit and supports multiple databases

The recovery catalog retains full backup history indefinitely across all databases, unlike the control file which is limited by CONTROL_FILE_RECORD_KEEP_TIME.

Which V$ view should a DBA query to determine the current apply lag on a physical standby database?

Answer: V$DATAGUARD_STATS

V$DATAGUARD_STATS contains metrics including apply lag, transport lag, and estimated failover time for the current standby database.

A DBA runs RMAN RESTORE PREVIEW. What does this command do?

Answer: Lists which backups and archive logs would be used in a restore, without performing it

RESTORE PREVIEW reports which backup sets and archive logs RMAN would use to perform a restore, acting as a dry run without any actual I/O.