Showing posts with label Fast Recovery Area. Show all posts
Showing posts with label Fast Recovery Area. Show all posts

Q&As: Fast Recovery Area (III)

(Q) What types of database files can be stored in the FAST RECOVERY AREA?

  • control file, online redo logs, archived redo logs, flashback logs, and RMAN backups

(Q) What two types of files, with respect to their use by the database, are kept in the FAST RECOVERY AREA?

  • Permanent files – Active files used by the database instance (control file, online redo logs)
  • Transient files – backups that may be deleted according to the retention policy

(Q) What happens if the instance cannot write to a multiplexed copy of the control file stored in the fast recovery area?

  • The instance fails.
  • Failure occurs EVEN if accessibel multiplexed copies are accessible outside the recovery area.

(Q) What is the difference between FLASH RECOVERY AREA and FAST RECOVERY AREA?

  • Just the name. FLASH became FAST with 11g

(Q) When configuring the FAST RECOVERY AREA, what happens if you specify DB_RECOVERY_FILE_DEST but DO NOT specify DB_RECOVERY_FILE_DEST_SIZE?

  • Specifying DB_RECOVERY_FILE_DEST without specifying DB_RECOVERY_FILE_DEST_SIZE is not allowed.

Q&As: Fast Recovery Area (I)

(Q) What is a Fast Recovery Area? What does it contain?

  • Is an Oracle managed space that can be used to hold RMAN disk backups, control file autobackups, and archived redo logs
  • Files here are maintained by Oracle and have an OMF format
  • Disk location in which the database can store and manage files related to backup and recovery. It contains:
  • (a) multiplexed copies of current control file and online redo logs, (b) archived redo logs (c) Foreign archived redo logs (d) flashback logs (e) image copies of datafiles and control files (f) backup pieces

(Q) What does Oracle recommends about the location of the Fast Recovery Area?

  • Should be on a separate disk from the database area (database files, control file, redo logs)

(Q) How can you find out the size of the Fast Recovery Area?

SQL> show parameter db_recovery

---------------------------- ----------- ------------------------------
db_recovery_file_dest      string  /u01/app/oracle/flash_recovery_area
db_recovery_file_dest_size   big integer 4977M

(Q) What is the default size of an online log created in the Fast Recovery Area?

  • 100 Mb

(Q) Which statements about Fast Recovery Area are correct?

  • ( ) Fast Recovery Area automates management of backup-related files.
  • ( ) It minimizes the need to manually manage disk space for backup-related files
  • ( ) It balances the use of space among the different types of files
  • ( ) When you create a Fast recovery area:
  • (a) you choose a location on disk and set an upper bound for storage space. (b) you set a backup retention policy
  • ( ) RMAN retains the data file backups required to satisfy the current retention policy AND any arquived redo logs required for complete recovery of those data file backups

Q&As: Fast Recovery Area (II)

(Q) What initialization parameters are used to configure a Fast Recovery Area?

  • DB_RECOVERY_FILE_DEST - specifies default location for fast recovery area.
  • DB_RECOVERY_FILE_DEST_SIZE - specifies (in bytes) the hard limit on the total space to be used by target database recovery files created in the fast recovery area
  • (optional) DB_FLASHBACK_RETENTION_TARGET -Specifies the upper limit (minutes) on how far back in time the database may be flashed back.

(Q) Can you configure the Fast Recovery Area on an ASM disk group?

  • Yes

(Q) How large should you configure the Fast Recovery Area?

  • At an ABSOLUTE MINIMUM, it should be large enough to containt the archived redo logs not yet on tape.
  • Scenario:
    • If you use incrementally updated backups and set the backup retention policy to REDUNDANCY 1, you can determine the size of the fast recovery area as below: