I did some research on this model as I was looking for a Home NAS box. Almost pulled the trigger until I found out that the maximum HDD size is 3TB for each of the (4) 3.5 inch bays in this unit has. That’s rather unfortunate as 4GB HDD would be better. The motherboard has 4x SATA spec 2 ports along w 2 SATA 3 spec ports.
Not sure as to what the size of the 2.5 inch HDD are but as Elmer FUd said “That’s All Folks”