ORA-19804: cannot reclaim N bytes disk space from M bytes limit

What does it mean?

Oracle tried to make room in the Fast Recovery Area (FRA) for a new file (archived log, backup, flashback log) but could not reclaim the required space because the logical limit defined by DB_RECOVERY_FILE_DEST_SIZE is reached.

Why does it happen?

The FRA size (DB_RECOVERY_FILE_DEST_SIZE) is an upper bound independent of the physical disk, and archived logs, RMAN backups or flashback logs have filled it. The root cause is usually archived logs not being backed up and deleted regularly, or obsolete backups not being purged.

How to fix it

Review FRA usage: SELECT * FROM v$recovery_area_usage; and SELECT * FROM v$recovery_file_dest; Back up archived logs to a destination outside the FRA and delete them (RMAN: BACKUP ARCHIVELOG ALL FORMAT '/backup/arc_%U' DELETE INPUT;) or purge backups that are no longer needed (RMAN: DELETE OBSOLETE;). With Data Guard, do not delete archived logs not yet applied on the standby. For a permanent fix, increase DB_RECOVERY_FILE_DEST_SIZE if there is disk space. If Flashback Database is not needed, consider disabling it.