Backup only user databases (schema + data) using mariadb-dump, then transfer safely using rsync. System schemas are excluded automatically.

mariadb-dump \
  --single-transaction \
  --quick \
  --routines \
  --triggers \
  --events \
  --hex-blob \
  --set-gtid-purged=OFF

Uses transactional snapshot dumping so production databases stay online.

SELECT schema_name
FROM information_schema.schemata
WHERE schema_name NOT IN (
 'mysql',
 'information_schema',
 'performance_schema',
 'sys'
);

rsync -aH --numeric-ids --delete \
  /var/backups/mariadb/ \
  backup@server:/srv/backups/mariadb/

gunzip -c db.sql.gz | mariadb -u root -p