Oracle has introduced Flashback Area from 10g and Now in 11g it has been improved a lot, when you enjoy sophisticated technologies, you have to bear with the maintenance part of it. Oracle Flashback Area is no exception to that.Flashback Area contains both archive logs and flashback logs(used for flashbacking the db and for other flashback operations).Lets assume that your FRA size is 20GB, and you take nightly archive log backups and clear the archivelogs nightly. what happens if the db does more transactions in one days and fills up the FRA? Big question?. As a traditional DBA you may think that deleting manually or moving the archive logs to other location will free up the space, but its not the case. if you use RMAN to backup and delete or delete then only the space is released, why is that? because Oracle maintains that info in a table called v$recovery_area_usage and though you manually delete or move logs in FRA , its not reflected Practically. this v$ view holds important piece of information, as how much % what is stored in FRA. you should be aware of the fact if you dont clear FRA then the database will become stale(no user cant login in db except sys and system) okay now comes the next trickiest part, what about flashback logs, in real terms you cant tell oracle to delete flashback logs, it keeps that till the init parameter flashback_retetion period and then purges it automatically. you can ask , what happens if i delete all my archive logs using RMAN but its full of flashback logs, well the space used by oracle flashback logs will be re used automatically , means when it reaches the full space in FRA oracle automatically deletes these flashback logs and clears up the space. still you can trick oracle think that the space is reached by setting the init parameter DB_RECOVERY_FILE_DEST_SIZE to null,by using the following syntax .SQL> alter system set DB_RECOVERY_FILE_DEST_SIZE=”; then oracle clears all flashback logs , then you can reset it to its original value.