QUESTION 34

You want to use the automatic management of backup and recovery operations features for your database.

Which configuration must you set?

A. Enable the flash recovery area and specify it as the archived redo log destination.

B. Disable the flash recovery area and start the database instance in ARCHIVELOG mode.

C. Enable the flash recovery area but do not specify it as the archived redo log destination.

D. Disable the flash recovery area and start the database instance in NOARCHIVELOG mode.

Answer: A

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Explanation/Reference:

答案解析：

官方参考：http://docs.oracle.com/cd/E11882_01/backup.112/e10642/rcmconfb.htm#BRADV89420


How Oracle Manages Disk Space in the Fast Recovery Area

Space in the fast recovery area is balanced among backups and archived logs that must be kept according to the retention policy, and other files that may be subject to deletion. Oracle Database does not delete eligible files from the fast recovery area until the space must be reclaimed for some other purpose. Files recently moved to tape are often still available on disk for use in recovery. The recovery area can thus serve as a cache for tape. When the fast recovery area is full, Oracle Database automatically deletes eligible files to reclaim space in the recovery area as needed.



Configuring Archived Redo Log Locations

Oracle recommends that you the use fast recovery area as an archiving location because the archived logs are automatically managed by the database. The generated file names for the archived logs in the fast recovery area are for Oracle Managed files and are not determined by the parameterLOG_ARCHIVE_FORMAT. Whatever archiving scheme you choose, it is always advisable to create multiple copies of archived redo logs.

You have the following basic options for archiving redo logs, listed from most to least recommended:

  1. Enable archiving to the fast recovery area only and use disk mirroring to create the redundancy needed to protect the archived redo logs.

    If DB_RECOVERY_FILE_DEST is specified and no LOG_ARCHIVE_DEST_n is specified, then LOG_ARCHIVE_DEST_10 is implicitly set to the recovery area. You can override this behavior by setting LOG_ARCHIVE_DEST_10 to an empty string.

  2. Enable archiving to the fast recovery area and set other LOG_ARCHIVE_DEST_n initialization parameter to locations outside the fast recovery area.

    If a fast recovery area is configured, then you can add the fast recovery area as an archiving destination by setting any LOG_ARCHIVE_DEST_n parameter toLOCATION=USE_DB_RECOVERY_FILE_DEST.

  3. Set LOG_ARCHIVE_DEST_n initialization parameters to archive only to non-fast recovery area locations.

If you use the fast recovery area, then you cannot use the LOG_ARCHIVE_DEST and LOG_ARCHIVE_DUPLEX_DEST initialization parameters. Using either of these parameters prevents you from starting the instance. Instead, set the LOG_ARCHIVE_DEST_n parameters. After your database is using LOG_ARCHIVE_DEST_n, you can configure a recovery area.

Note also that if you enable archiving but do not set any value for LOG_ARCHIVE_DEST, LOG_ARCHIVE_DEST_n, or DB_RECOVERY_FILE_DEST, then the redo logs are archived to a default location that is platform-specific. For example, on Solaris the default is ?/dbs.