OCP 1Z0 052 80

80. You perform differential incremental level 1 backups of your database on each working day and level 0 
backup on Sundays, to tape.  
Which two statements are true about differential incremental backups? (Choose two.) 
A.The backup performed on Sundays contains all the blocks that have ever been used in the database. 
B.The backup performed on Sundays  contains all  the blocks  that have  changed  since  the  last  level 1 
backup. 
C.The backup performed on each working day contains all  the blocks  that have changed since  the  last 
level 0 backup. 
D.The backup performed on Monday contains all the blocks that have changed since the level 0 backup, 
and every other working day contains all the blocks that have changed since the level 1 backup. 
Answer: AD

level 0 备份所有，level 1 备份自最后一次0级或1级以后的变动

Incremental Backups of Data Files

RMAN incremental backups copy only those blocks in a data file that change between backups. A level 0 incremental backup, which copies all blocks in the data file, is used as a starting point for an incremental backup strategy.

Incremental backups at level 1 copy only images of blocks that have changed since a previous incremental backup. Level 1 backups can becumulative, in which case all blocks changed since the most recent level 0 backup are included, or differential, in which case only blocks changed since the most recent level 0 or level 1 incremental backup are included. A typical incremental strategy makes level 1 backups at regular intervals such as once each day.

Recovering changed blocks from incremental backups can speed media recovery. Because an incremental level 1 backup copies the final contents of all data file blocks changed during the period covered by the incremental backup strategy, the recovery process can avoid reapplying updates from the archived redo log files of that period, and update each block with its final contents. The archived redo log files are used only for changes from the period not covered by level 1 backups.