OCP-1Z0-053-V13.02-502题

502.A database is running In ARCHIVBXXMS mode. It has two online redo log groups and each group

has one member.

A LGWR Input/output (I/O) fells due to permanent media failure that has resulted In the loss of redo log

file and the LWGR terminates causing the instance to crash. The steps to recover from the loss of a

current redo log group member in the random order are as follow.

1) Restore the corrupted redo log group.

2) Restore from a whole database backup.

3) Perform incomplete recovery.

4) Relocate by renaming the member of the damaged online redo log group to a new location.

5) Open the database with the RESETLOGS option.

6) Restart the database instance.

7) Issue a checkpoint and clear the log.

Identify the option with the correct sequential steps to accomplish the task efficiently.

A. 1, 3, 4, and 5

B. 7, 3, 4. and 5

C. 2, 3, 4, and 5

D. 7, 4, 3. and 5

E. Only 6 is required

Answer: B

答案解析：

参考：http://docs.oracle.com/cd/E11882_01/backup.112/e10642/osadvsce.htm#BRADV90049

B为正确答案

Recovering After Losing All Members of an Online Redo Log Group

If a media failure damages all members of an online redo log group, then different scenarios can occur depending on the type of online redo log group affected by the failure and the archiving mode of the database.

If the damaged online redo log group is current and active, then it is needed for crash recovery; otherwise, it is not. Table 30-4 outlines the various recovery scenarios.

Table 30-4 Recovering After the Loss of an Online Redo Log Group

If the Group Is...Then...And You Should...

Inactive

It is not needed for crash recovery

Clear the archived or unarchived group.

Active

It is needed for crash recovery

Attempt to issue a checkpoint and clear the log; if impossible, then you must either use Flashback Database or restore a backup and perform incomplete recovery up to the most recent available redo log.

Current

It is the redo log that the database is currently writing to

Attempt to clear the log; if impossible, then you must either use Flashback Database or restore a backup and perform incomplete recovery up to the most recent available redo log.

Recovering from Loss of Active Logs in ARCHIVELOG Mode

In this scenario, the database archiving mode is ARCHIVELOG.

To recover from loss of an active online redo log group in ARCHIVELOG mode:

1. Begin incomplete media recovery, recovering up through the log before the damaged log.

2. Ensure that the current name of the lost redo log can be used for a newly created file. If not, then rename the members of the damaged online redo log group to a new location. For example, enter:

   ALTER DATABASE RENAME FILE "/disk1/oradata/trgt/redo01.log" TO "/tmp/redo01.log";ALTER DATABASE RENAME FILE "/disk1/oradata/trgt/redo02.log" TO "/tmp/redo02.log";

3. Open the database using the RESETLOGS option:

   ALTER DATABASE OPEN RESETLOGS;