OCP-1Z0-053-V12.02-505题

505.You configured the default backup device type as disk for RMAN backups. In your database, because

of business requirements, you have to take a simultaneous duplicate backup of the data files when the

RMAN BACKUP command is used.

What must you set using the RMAN CONFIGURE command to achieve this?

A. MAXSETSIZE TO 2;

B. DEVICE TYPE DISK PARALLELISM 2;

C. RETENTION POLICY TO REDUNDANCY 2;

D. DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 2;

Answer: C

答案解析：

参考：http://docs.oracle.com/cd/E11882_01/backup.112/e10642/rcmbckad.htm#BRADV89571

根据官方文档，正确答案为D

Duplexing Backup Sets with CONFIGURE BACKUP COPIES

As explained in "Configuring Backup Duplexing", the CONFIGURE ... BACKUP COPIES command specifies the number of identical backup sets to create on the specified device type. This setting applies to all backup sets except control file autobackups (because the autobackup of a control file always produces one copy) and backup sets when backed up with the BACKUP BACKUPSET command.

To duplex a backup with CONFIGURE ... BACKUP COPIES:

1. Configure the number of copies on the desired device type for datafiles and archived redo logs on the desired device types.

   By default, CONFIGURE ... BACKUP COPIES is set to 1 for each device type. The following example configures duplexing for datafiles and archived logs on tape and also duplexing for datafiles (but not archived redo logs) on disk:

   CONFIGURE DEVICE TYPE sbt PARALLELISM 1;

   CONFIGURE DEFAULT DEVICE TYPE TO sbt;

   CONFIGURE CHANNEL DEVICE TYPE DISK FORMAT '/disk1/%U', '/disk2/%U';

   CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE sbt TO 2;

   CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE sbt TO 2;

   CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 2;

2. Execute the BACKUP command.

   The following command backs up the database and archived logs to tape, making two copies of each data file and archived log:

   BACKUP AS BACKUPSET DATABASE PLUS ARCHIVELOG;

   Because of the configured formats for the disk channel, the following command backs up the database to disk, placing one copy of the backup sets produced in the /disk1 directory and the other in the /disk2 directory:

   BACKUP DEVICE TYPE DISK AS BACKUPSET DATABASE;

   If the FORMAT clause were not configured on CONFIGURE CHANNNEL, then you specify FORMAT on the BACKUP command itself. For example, you issue the following command:

   BACKUP AS BACKUPSET DATABASE

     FORMAT '/disk1/%U',

            '/disk2/%U';

3. Issue a LIST BACKUP command to see a listing of backup sets and pieces.

   For example, enter the following command:

   LIST BACKUP SUMMARY;

   The #Copies column shows the number of backup sets, which may have been produced by duplexing or by multiple backup commands.