Home » Oracle » 1z0-053 » Which of the following are true concerning block media recovery?
Which of the following are true concerning block media recovery? (Choose all that apply.)
A. Any gap in archive logs ends the recovery.
B. If a gap in archive logs is encountered, RMAN will search forward for newer versions of the blocks that are not corrupt.
C. Uncorrupted blocks from the flashback logs may be used to speed recovery.
D. The database can be in NOARCHIVELOG mode.
E. None of the above.
Correct Answer: BC
Explanation/Reference:
Explanation:
Overview of Block Media Recovery (link)
Basic Concepts of Block Media Recovery
Whenever block corruption has been automatically detected, you can perform block media recovery manually with the RECOVER … BLOCK command.
By default, RMAN first searches for good blocks in the real-time query physical standby database, then flashback logs and then blocks in full or level 0 incremental backups.
Prerequisites for Block Media Recovery (link)
The following prerequisites apply to the RECOVER … BLOCK command:
If only proxy copy backups exist, then you can restore them to a nondefault location on disk, in which case RMAN considers them data file copies and searches them for blocks during block media recovery.
RMAN cannot use level 1 incremental backups. Block media recovery cannot survive a missing or inaccessible archived redo log, although it can sometimes survive missing redo records.
If flashback logging is enabled and contains older, uncorrupted versions of the corrupt blocks, then RMAN can use these blocks, possibly speeding up the recovery.
Restore Failover (link)
RMAN automatically uses restore failover to skip corrupted or inaccessible backups and look for usable backups. When a backup is not found, or contains corrupt data, RMAN automatically looks for another backup from which to restore the desired files.
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