OCP-1Z0-053-V12.02-590题

590.Which type of backup backs up only data blocks modified since the most recent backup at the same

level or lower?

A. Differential incremental backup

B. Different incremental backup

C. Cumulative backup

D. Cumulative incremental backup

Answer: A

答案解析：

增量备份参考： http://blog.csdn.net/rlhua/article/details/11763453

增量累积备份参考：http://blog.csdn.net/rlhua/article/details/11763671

参考：http://docs.oracle.com/cd/E11882_01/backup.112/e10642/glossary.htm#BRADV90151

differential incremental backup

A type of incremental backup that backs up all blocks that have changed since the most recent backup at level 1 or level 0. For example, in a differential level 1 backup RMAN determines which level 1 or level 0 incremental backup is most recent and then backs up all blocks changed since that backup. Differential backups are the default type of incremental backup. When recovering using differential incremental backups, RMAN must apply all differential incremental level 1 backups since the restored data file backup.

参考：http://docs.oracle.com/cd/E11882_01/backup.112/e10642/rcmcncpt.htm#BRADV89500

Differential Incremental Backups

In a differential level 1 backup, RMAN backs up all blocks that have changed since the most recent incremental backup at level 1 (cumulative or differential) or level 0. For example, in a differential level 1 backup, RMAN determines which level 1 backup occurred most recently and backs up all blocks modified after that backup. If no level 1 is available, then RMAN copies all blocks changed since the base level 0 backup.

If no level 0 backup is available in either the current or parent incarnation, then the behavior varies with the compatibility mode setting. If compatibility is >=10.0.0, RMAN copies all blocks that have been changed since the file was created. Otherwise, RMAN generates a level 0 backup.

Figure 8-2 Differential Incremental Backups

Description of "Figure 8-2 Differential Incremental Backups"

In the example shown in Figure 8-2, the following activity occurs each week:

• Sunday

  An incremental level 0 backup backs up all blocks that have ever been in use in this database.

• Monday through Saturday

  On each day from Monday through Saturday, a differential incremental level 1 backup backs up all blocks that have changed since the most recent incremental backup at level 1 or 0. The Monday backup copies blocks changed since Sunday level 0 backup, the Tuesday backup copies blocks changed since the Monday level 1 backup, and so forth.

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