Traefik has no built-in log rotation and no SIGUSR1/reopen handling.
--accesslog.filePath and --log.filePath (traefik.yaml) write directly
to /volume1/docker/traefik/logs, which had grown to 15.5GB unrotated,
contributing to disk pressure (docker-2 CephFS at 82%) and adding
write latency to every request through Traefik.