If you are moving from an old Synology to a new Synology NAS, or just want to keep two NAS in sync at all times, the simple-yet-effective solution I’ve found is to use Shared Folder Sync with rsync.

Obviously file transfer speeds is what it's all about, and nobody wants a storage device that is capable of supporting 8TBs of data if it takes the better part of the year to get it there. Therefore ...