I recently replaced the HDs using the advice of this and other TS forums:
1) Delete RAID
2) Shutdown
3) Replace drive 2
4) Format drive 2
5) Repeat steps 2-4 for HDs 3, 4, 1
6) Create RAID
I replaced the 4 original 500GB Hitachi drives with 4 new, otherwise identical, 2TB Hitachi drives. I upgraded the firmware to 1.04. The web interface comes up fine. Attached is what the drive setup looks like from the web interface. Drives 3 and 4 are identical as well.
When I build and check the array, it shows 4x 2TB drives making 1.7TB in a RAID-5 as opposed to the expected 6TB. How can I build the array correctly?
Thanks!

i believe if you go over the factory capacity which was 2 or 4 tb's for this device it probably won't recognize any more then that. Could be an issue, if you had a ts3, or ts pro 2 you could go 8tb high.