OCP-1Z0-053-V12.02-160题

160.Which two statements are true about the duplexing of the backups taken by RMAN? (Choose two.)

A. It's only supported for the backups performed on the tape

B. It is not supported for backup operations that produce image copies

C. Duplex backups need a parallelism for the device to be equal to number of copies

D. Duplex backups can be performed to either disk or tape, but cannot be performed on tape and disk simultaneously

Answer: BD

答案解析：

参考：http://docs.oracle.com/cd/E11882_01/backup.112/e10642/rcmconfa.htm#BRADV140

Configuring Backup Duplexing

You can use the CONFIGURE ... BACKUP COPIES command to specify how many copies of each backup piece should be created on the specified device type for the specified type of file. This type of backup is known as a duplexed backup set. The CONFIGURE settings for duplexing only affect backups of data files, control files, and archived logs into backup sets, and do not affect image copies.

Note:

A control file autobackup is never duplexed.

RMAN can duplex backups to either disk or tape, but cannot duplex backups to tape and disk simultaneously. When backing up to tape, ensure that the number of copies does not exceed the number of available tape devices. The following examples show possible duplexing configurations:

# Makes 2 disk copies of each data file and control file backup set

# (autobackups excluded)

CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 2;

# Makes 3 copies of every archived redo log backup to tape

CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE sbt TO 3;

To return a BACKUP COPIES configuration to its default value, run the same CONFIGURE command with the CLEAR option, as in the following example:

CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE sbt CLEAR;

By default, CONFIGURE ... BACKUP COPIES is set to 1 for each device type.

Note:

If you do not want to create a persistent copies configuration, then you can specify copies with the BACKUP COPIES and the SET BACKUP COPIES commands.