OCP-1Z0-053-V13.02-601题

601.You need to perform a block media recovery on the tools01.dbf data file in the SALES database by using Recovery Manager (RMAN).

Which two are the prerequisites to perform this operation? (Choose two)

A. You must configure block change tracking file

B. You must have first level 1 backups for RMAN to restore blocks

C. You must ensure that the SALES database is mounted or open

D. You must have full or level 0 backups for RMAN to restore blocks

E. You must take the tools01.dbf data file offline before you start a block media recovery

Answer: CD

答案解析：

题意：要求使用RMAN来 perform a block media recovery在tools01.dbf 数据文件上，在SALES database上。

在恢复时，数据库必须处于mount状态或者open状态，以及有包含该数据文件备份信息所有的备份集。

故选CD

参考：http://docs.oracle.com/cd/E11882_01/backup.112/e10642/rcmblock.htm#BRADV89785

Prerequisites for Block Media Recovery

The following prerequisites apply to the RECOVER ... BLOCK command:

• The target database must run in ARCHIVELOG mode and be open or mounted with a current control file.

• If the target database is a standby database, then it must be in a consistent state, recovery cannot be in session, and the backup must be older than the corrupted file.

• The backups of the data files containing the corrupt blocks must be full or level 0 backups and not proxy copies.

  If only proxy copy backups exist, then you can restore them to a nondefault location on disk, in which case RMAN considers them data file copies and searches them for blocks during block media recovery.

• RMAN can use only archived redo logs for the recovery.

  RMAN cannot use level 1 incremental backups. Block media recovery cannot survive a missing or inaccessible archived redo log, although it can sometimes survive missing redo records.

• Flashback Database must be enabled on the target database for RMAN to search the flashback logs for good copies of corrupt blocks.

  If flashback logging is enabled and contains older, uncorrupted versions of the corrupt blocks, then RMAN can use these blocks, possibly speeding up the recovery.

• The target database must be associated with a real-time query physical standby database for RMAN to search the database for good copies of corrupt blocks.