Why won rsync retain my UIDs/GIDs?
To maintain access compatibility with other protocols, rsyncd will transfer files as the share user in Share security mode. This means that files transferred to the NAS over rsync will be owned by the share user. To maintain UIDs/GIDs, use User security mode, or NFS mount the share with root-enabled hosts properly set in the NFS configuration tab in Frontview and do a pseudo-local rsync.