Which of the following statements are true about the BACKUP command? (Choose all that
apply.)
A.
The BACKUP command can not be used to make image copies of a datafile.
B.
The BACKUP command can improve performance by multiplexing backup files.
C.
The BACKUP can take advantage of the block-change tracking capability.
D.
The BACKUP command cannot store data in incremental backups.
E.
The BACKUP command can store data in cumulative incremental backups only.
B and C are correct:
http://docs.oracle.com/cd/E11882_01/backup.112/e10643/rcmsynta007.htm#RCMRF107
B:
The DISKRATIO parameter is easier for data file backups when the data files are striped or reside on separate disk spindles and you either:
Use a high-bandwidth tape drive that requires several data files to be multiplexed to keep the tape drive streaming.
C:
Make backups while the database is open and you must spread the I/O load across several disk spindles to leave bandwidth for online operations.
You can improve incremental backup performance by enabling block change tracking on a primary or standby database. In this case, RMAN keeps a record of which blocks have changed in the block change tracking file.