noarchivelog模式下增量备份的恢复

ocp 053

685. In your test database:

-You are using Recovery Manager (RMAN) to perform incremental backups of your test database

-The test database is running in NOARCHIVELOG mode

-One of the data files is corrupted

-All online redo log files are lost because of a media failure

Which option must you consider in this scenario?

A.Configuring the database in ARCHVIELOG mode and  then using incremental backup to recover the database

B.Using incremental backup to recover the damaged data file and then manually creating the online redo log files

C.Creating a new test database because  the database is not recoverable du e to the fact that the database is configured in NOARCHIVELOG mode

D.Using incremental backups to recover the database by using the RECOVER DATABASE NOREDO command and then using the RESETLOGS option to open the database.  

Answer: C 

答案解析：

参考：http://docs.oracle.com/cd/E11882_01/backup.112/e10643/rcmsynta2001.htm#RCMRF90258

根据官方文档，此题应该选D

Example 3-6 Recovering a NOARCHIVELOG Database

You can perform limited recovery of changes to a database running in NOARCHIVELOG mode by applying incremental backups. The incremental backups must be consistent, like all backups of a database run in NOARCHIVELOG mode, so you cannot back up the database when it is open.

Assume that you run database prod in NOARCHIVELOG mode with a recovery catalog. You shut down the database consistently and make a level 0 backup of database prod to tape on Sunday afternoon. You shut down the database consistently and make a level 1 differential incremental backup to tape at 3:00 a.m. on Wednesday and Friday.

On Saturday, a media failure destroys half the data files and the online redo logs. Because the online logs are lost, you must specify the NOREDO option in the RECOVER command. Otherwise, RMAN searches for the redo logs after applying the Friday incremental backup and issues an error message when it does not find them.

After connecting RMAN to prod and the catalog database, recover as follows:

STARTUP FORCE NOMOUNT;

RESTORE CONTROLFILE;      # restore control file from consistent backup

ALTER DATABASE MOUNT;

RESTORE DATABASE;         # restore data files from consistent backup

RECOVER DATABASE NOREDO;  # specify NOREDO because online redo logs are lost

ALTER DATABASE OPEN RESETLOGS;

The recovered database reflects only changes up through the time of the Friday incremental backup. Because there are no archived redo log files, there is no way to recover changes made after the incremental backup.