Which of the following is NOT an advantage of block media recovery (BMR)?
A.
Reduced MTTR.
B.
Datafiles remain offline while corrupt blocks are repaired.
C.
Datafiles remain online while corrupt blocks are repaired.
D.
A and C
Explanation:
Overview of Block Media Recovery (link)
Purpose of Block Media Recovery
You can use block media recovery to recover one or more corrupt data blocks within a data
file. Block media recovery provides the following advantages over data file media recovery:
Lowers the mean time to recover (MTTR) because only blocks needing recovery are
restored and recovered
Enables affected data files to remain online during recovery
Without block media recovery, if even a single block is corrupt, then you must take the data
file offline and restore a backup of the data file. You must apply all redo generated for the
data file after the backup was created. The entire file is unavailable until media recovery
completes. With block media recovery, only the blocks actually being recovered are
unavailable during the recovery.
Block media recovery is most useful for physical corruption problems that involve a small,
well-known number of blocks. Block-level data loss usually results from intermittent, random
I/O errors that do not cause widespread data loss, and memory corruptions that are written
to disk. Block media recovery is not intended for cases where the extent of data loss or
corruption is unknown and the entire data file requires recovery. In such cases, data file
media recovery is the best solution.