TIP: For my part, in order to avoid to traffic on the network, faster to copy my old records, I put them by turns in on the server and USB transfers are locally giving orders from the HTML interface ... is fast but it works only blind ... LED flash disks for hours.
Be careful though, the installed drives are consistently formatted in EXT4 (linux) ... so you have to have at least one blank disc to boot.
A small 4/5 because of the rather rustic HTML interface regarding file management. As I said, we copy blindly.
;-)