The fast recovery area is a unified storage location for all Oracle Database files related to recovery. Enabling rapid backups for recent data can reduce requests to system administrators to retrieve backup tapes for recovery operations.
Database administrators can define the DB_RECOVERY_FILE_DEST parameter to the path for the fast recovery area to enable on disk backups and rapid recovery of data. When you enable fast recovery in the
init.ora file, Oracle Database writes all RMAN backups, archive logs, control file automatic backups, and database copies to the fast recovery area. RMAN automatically manages files in the fast recovery area by deleting obsolete backups and archiving files no longer required for recovery.
Oracle recommends that you create a fast recovery area disk group. Oracle Clusterware files and Oracle Database files can be placed on the same disk group, and you can also place fast recovery files in the same disk group. However, Oracle recommends that you create a separate fast recovery disk group to reduce storage device contention.
The fast recovery area is enabled by setting the DB_RECOVERY_FILE_DEST parameter. The size of the fast recovery area is set with DB_RECOVERY_FILE_DEST_SIZE. As a general rule, the larger the fast recovery area, the more useful it becomes. For ease of use, Oracle recommends that you create a fast recovery area disk group on storage devices that can contain at least three days of recovery information. Ideally, the fast recovery area is large enough to hold a copy of all of your data files and control files, the online redo logs, and the archived redo log files needed to recover your database using the data file backups kept under your retention policy.
Multiple databases can use the same fast recovery area. For example, assume you have created a fast recovery area disk group on disks with 150 GB of storage, shared by 3 different databases. You can set the size of the fast recovery for each database depending on the importance of each database. For example, if database1 is your least important database, database2 is of greater importance, and database3 is of greatest importance, then you can set different DB_RECOVERY_FILE_DEST_SIZE settings for each database to meet your retention target for each database: 30 GB for database1, 50 GB for database2, and 70 GB for database3.