The components that creates different backup and recovery-related files have no knowledge of each other or of the size of the file systems where they store their data. With Automatic Disk-Based Backup and Recovery, you can create a flash recovery area, which automates management of backup-related files. Choose a location on disk and an upper bound for storage space, and set a retention policy that governs how long backup files are needed for recovery, and the database manages the storage used for backups, archived redo logs, and other recovery-related files for your database within that space. Files no longer needed are eligible for deletion when RMAN needs to reclaim space for new files.
Using a flash recovery area minimizes the need to manually manage dsk space for your backup-related files and balance the use of space among the different types of files. Oracle recommends that you enable a flash recovery area to simplify your backup management.