Create Fast Recovery Area disk group (FRA).

The Fast Recovery Area is a unified storage location for all Oracle Database files related to recovery. 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. Enabling rapid backups for recent data can reduce requests to system administrators to retrieve ackup tapes for recovery operations.

When you enable Flash Recovery in the init.ora file, all RMAN backups, archive logs, control file automatic backups, and database copies are written to the Fast Recovery Area. RMAN automatically manages files in the Fast Recovery Area by deleting obsolete backups and archive 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 flash recovery files in the same disk group. However, Oracle
recommends that you create a separate Flash Recovery disk group to reduce storage
device contention.

The Fast Recovery Area is enabled by setting DB_RECOVERY_FILE_DEST. 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 should be 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 one Fast Recovery Area disk group on disks with 150 GB of storage, shared by three different databases. You can set the size of the Fast Recovery Area for each database depending on the importance of each database. For example, if database1 is your least important database, database 2 is of greater importance and database 3 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 database 1, 50 GB for database 2, and 70 GB for database 3.