>>473
RESOLVED: Logging into Synology SSH using a key instead of a password
https://forum.synology.com/enu/viewtopic.php?t=126166
で解決してrsync使えてたんだが突然下記エラー出て使えなくなった
DSM更新等環境変更は一切なし
再起動しても変化なし

sending incremental file list
ERROR: module is read only
rsync error: syntax or usage error (code 1) at main.c(1131) [Receiver=3.0.9]
rsync error: rsync service is no running (code 43) at io.c(687) [sender=3.0.9]

同様の症例↓
https://serverfault.com/questions/425589/rsync-over-ssh-error-module-is-read-only-suddenly-appeared
https://forum.synology.com/enu/viewtopic.php?t=56409
https://forum.synology.com/enu/viewtopic.php?t=105375