1. Add disk space and increase DB_RECOVERY_FILE_DEST_SIZE.
2. Backup files to tertiary device using RMAN.
3. Consider changing RMAN retention policy.
4. Consider changing RMAN archived log deletion policy.
5. Delete files from recovery area using RMAN.
1. A database crash happened during file creation.
2. A backup control file was restored.
3. The control file was re-created.
4. DB_RECOVERY_FILE_DEST has previously been enabled and then disabled.