The Deskstar 7K1000.B - Model HDT721010SLA360 Hitachi drives are currently having issues when used with the DNS-321, 323 and 343. Follow these steps in order to use these drives with your D-Link NAS product:
Step 1: Log in to the devices Web Configuration
Step 2: Select Tools
Step 3: Click the Restart button.
This will allow the D-Link NAS to detect and configure your drives.
Note: This must be done each time your D-Link NAS is power on and will be fixed in the next firmware update.