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.
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:
The target database must run in ARCHIVELOG mode and be open or mounted with a current control file.
If the target database is a standby database, then it must be in a consistent state, recovery cannot be in
session, and the backup must be older than the corrupted file.
The backups of the data files containing the corrupt blocks must be full or level 0 backups and not proxy copies.
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 inaccessiblearchived redo log, although it can sometimes survive missing redo records.
Flashback Database must be enabled on the target database for RMAN to search the flashback logs for good
copies of corrupt blocks. 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. The target database must be
associated with a real-time query physical standby database for RMAN to search the database for good copies
of corrupt blocks.
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.