ORA-00257: Archiver error. Connect internal only, until freed

What does it mean?

The archiver (ARCH) process cannot archive redo logs; usually the archive destination (FRA or archive log destination) is full. The database suspends new transactions.

Why does it happen?

The Flash Recovery Area (DB_RECOVERY_FILE_DEST) or archive log destination is full, disk space has run out, RMAN backups are not deleting archive logs, or the DB_RECOVERY_FILE_DEST_SIZE limit has been reached.

How to fix it

Free up space: back up old archive logs with RMAN to a destination outside the FRA and delete them: RMAN> BACKUP ARCHIVELOG ALL FORMAT '/backup/arc_%U' DELETE INPUT (writing the backup to the FRA while it is full fails). With Data Guard, do not delete archives not yet shipped to or applied on the standby; otherwise a gap forms on the standby (CONFIGURE ARCHIVELOG DELETION POLICY TO APPLIED ON ALL STANDBY). View FRA usage: SELECT * FROM v$recovery_file_dest / v$flash_recovery_area_usage. Temporarily increase DB_RECOVERY_FILE_DEST_SIZE or move the destination to a larger disk. Check free space at the disk level. Establish a regular archive cleanup policy.