053试题 160/505 - Duplexed Backup Sets
题目：
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
参考答案 BD
解析
题目意思问，关于RMAN备份的duplex，那个说法是正确的。
RMAN可以将备份duplex复制到磁盘或磁带，但不能同时将备份复制到磁带和磁盘 。所以A错误。D正确。
生成映像副本的备份操作不支持duplex. B正确。
duplex备份需要并行，有几个duplex就需要几个并行。说法错误的。C错误。
参考文档：
https://docs.oracle.com/cd/E11882_01/backup.112/e10642/rcmcncpt.htm#BRADV89491
Duplexed Backup Sets
When backing up datafiles, archived redo log files, server parameter files, and control files into backup pieces, RMAN can create a duplexed backup set, producing up to four identical copies of each backup piece in the backup set on different backup destinations with one BACKUP command. Duplexing is not supported for backup operations that produce image copies.
You can use the COPIES parameter in the CONFIGURE, SET, or BACKUP commands to specify duplexing of backup sets when using the BACKUP command. 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 FORMAT parameter of the BACKUP command specifies the destinations for duplexed backups. The following example creates three copies of the backup of data file 7:
BACKUP DEVICE TYPE DISK COPIES 3 DATAFILE 7
FORMAT '/disk1/%U','?/oradata/%U','?/%U';
RMAN places the first copy of each backup piece in /disk1, the second in ?/oradata, and the third in the Oracle home. RMAN does not produce three backup sets, each with a different unique backup set key. Rather, RMAN produces one backup set with a unique key, and generates three identical copies of each backup piece in the set.
https://docs.oracle.com/cd/E11882_01/backup.112/e10642/rcmconfa.htm#BRADV139
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.
See Also:
-
"Multiple Copies of RMAN Backups" for an overview of duplexed backups
-
"Duplexing Backup Sets" to learn how to create duplexed backups
-
Oracle Database Backup and Recovery Reference for
BACKUPsyntax -
Oracle Database Backup and Recovery Reference for
CONFIGUREsyntax -
Oracle Database Backup and Recovery Reference for
SETsyntax
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题目：
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;
参考答案 C
解析
配置备份的缺省是disk。因为业务需要，需要执行一个simultaneous duplicate backup 。问怎么样实现。
选择D
参考文档，参考上面的题目的文档。
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