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DBA2 - Fast Recovery Area

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• DBA2 - Fast Recovery Area
  • Fast Recovery Area
    • Configuring the Fast Recovery Area
    • Monitoring the Fast Recovery Area
  • Lab: Query current info of FRA
  • Lab: Alter the destination and size of fra

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Fast Recovery Area

Configuring the Fast Recovery Area

• Fast recovery area:

  • space that is set aside on disk to contain

    • archived logs,
    • backups,
    • flashback logs,
    • multiplexed control files,
    • and multiplexed redo logs.
  • simplifies backup storage management and is strongly recommended.
  • should be placed on storage space that is separate from the location of your database data files, primary online log files, and control file.

• The amount of disk space to allocate for the fast recovery area depends on the size and activity levels of your database.

  • As a general rule, the larger the fast recovery area, the more useful it is.
  • Ideally, the fast recovery area should be large enough for copies of your data and control files and for flashback, online redo, and archived logs needed to recover the database with the backups kept based on the retention policy.
  • In short, the fast recovery area should be at least twice the size of the database so that it can hold one backup and several archived logs.
  • Location specified by the DB_RECOVERY_FILE_DEST parameter
  • Size specified by the DB_RECOVERY_FILE_DEST_SIZE parameter

• Space management in the fast recovery area is governed by a backup retention policy.

  • A retention policy determines when files are obsolete, which means that they are no longer needed to meet your data recovery objectives.
  • The Oracle Database server automatically manages this storage by deleting files that are no longer needed.

• Configuration of the fast recovery area includes specifying the location, size, and retention policy.

ALTER SYSTEM SET db_recovery_file_dest = directory | disk group
ALTER SYSTEM SET db_recovery_file_destsize = integer [K | M | G]

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Monitoring the Fast Recovery Area

• Monitor the fast recovery area to ensure that it does not reach its capacity.

• If the instance is unable to create an archived log because of lack of space, it pauses until the administrator corrects the situation.

  • Query the V$RECOVERY_FILE_DEST view to determine the current location, disk quota, space in use, space reclaimable by deleting files, and total number of files in the fast recovery aroa.
  • Query the V$RECOVERY_AREA_USAGE view to determine the percentage of the total disk quota used by different types of files.
  • You can also use GUI tools such as Enterprise Manager Cloud Control to monitor the space usago.

• The retention time determines when files are obsolete (that is, when they are no longer needed to meet your data recovery objectives).

  • The Oracle Database server automatically manages this storage, deleting files that are no longer needed.自动管理, 自动删除

• You can back up the recovery area so that Oracle Recovery Manager (RMAN) can fail over to other archived redo log destinations if the archived redo log in the fast recovery area is inaccessible or corrupted.可以备份该区域

  • Periodically copying backups to tape frees space in the fast recovery area for other files, but retrieving files from tape causes longer database restoration and recovery times.

• Parameters:

  • If the DB_RECOVERY_FILE_DEST and DB_RECOVERY_FILE_DEST_SIZE parameters values are not null, the fast recovery area is enabled.
  • Specifying DB_RECOVERY_FILE_DEST parameter without also specifying the DB_RECOVERY_FILE_DEST_SIZE initialization parameter is not allowed. 必须两个同时设置
  • The change of the fast recovery area’s size do not require to restart the database because the DB_RECOVERY_FILE_DEST_SIZE parameter is dynamic.

Parameters	Description
DB_RECOVERY_FILE_DEST	null,Default location for the flash recovery area.
DB_RECOVERY_FILE_DEST_SIZE	null, size of flash recovery area.

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Lab: Query current info of FRA

-- View the current FRA
show parameter db_recovery_file_dest;
-- NAME                       TYPE        VALUE
-- -------------------------- ----------- ---------------------------
-- db_recovery_file_dest      string      /u01/app/oracle/oradata/fra
-- db_recovery_file_dest_size big integer 10G

• Location of FRA

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Lab: Alter the destination and size of fra

-- View the current FRA
show parameter db_recovery_file_dest;

-- alter system to change the path of fra
ALTER SYSTEM SET db_recovery_file_dest='/u01/app/oracle/fast_recovery_area' SCOPE=both;
ALTER SYSTEM SET db_recovery_file_dest_size=10G SCOPE=both;

-- Confirm the current FRA
show parameter db_recovery_file_dest;

# copy all files and dir from old fra to the new fra
cp -Rf /u01/app/oracle/oradata/fra/ORCL/. /u01/app/oracle/fast_recovery_area/ORCL/

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