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Oracle OCP 1Z0 053 Q401(Block Media Recovery)

原创 Oracle 作者:abstractcyj 时间:2016-04-06 14:46:04 0 删除 编辑
401.Which of the following are correct about block media recovery? (Choose all that apply.)
A. Physical and logical block corruption is recorded automatically in V$DATABASE_BLOCK_
CORRUPTION.
B. Logical corruptions are repairable by BMR.
C. Physical corruptions are repairable by BMR.
D. RMAN can use any backup for a BMR restore.
E. ARCHIVELOG mode is not required if you have both a full and incremental backup for restore.
Answer: AC

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.



参考:http://blog.itpub.net/17013648/viewspace-1292381/

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曾从事java方向开发多年。近年已经转入数据库方向。主要擅长SQL优化,Oracle数据库问题诊断,Oracle备份与恢复等。服务于医药物流,医院等行业

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