I get a barebone DNS-320 without hard disk for RM 199 (about USD 65). The hard disk cost much more than that.
EOL. This product was phase out on January? 2012 (EOL, end of life). According to the website, EOL means the product is not sold any more. You may consider DNS-320L cloud, which was available at the time I bought 320, price at 50% more (still cheap).
3TB support. If you are interested to use 3Tb hard disk, you might need to check the hardware and firmware version, which will be stated at the bottom of the package box. Mine is H/W version A2 F/W version 2.02. You need firmware 2.02 to support 3Tb, latest firmware is 2.03. Make sure your hardware is upgradable with firmware version 2.02.
Firmware and setup software is available at D-Link support site for DNS-320.
Some people experience the hard disk shown up as 4xxMB capacity, is a common problem. I experienced it as well after the first time system shutdown. I reformat the disk again, but still not sure how it happens. If you were worried, use 2Tb or lower capacity.
Installation and setup. Just follow the installation guide. It should not be a big issue for most people.
Startup/shutdown. There is a small button on the right side of the front panel, press to start up. Press and hold to shutdown. Or you can shutdown from web UI, Menu, Management, System Management, System Settings, Shutdown.
You can schedule your shutdown time for each days as well.
Create share folder. Share folder is the folder that you can see from the Windows file explorer. The NAS will share out the volume without password protection as default, you can disable it and share out other folders with password protected.
To create new share folder, Web UI, Menu, Management, Account Management, Network Shares, New...
Quite a number of user having problem with create new share folder. You need to click on the text to open sub folder, or create new folder.
Click on the text to open sub-folder or create new folder
Select the folder to be share out.
AFP vs Samba/SMB/CIFS. DNS-320 use CIFS/SMB by default. Mac OS X is able to access with smb. OS X Finder Menu, Go, Connect to server... smb://192.168.1.100 (just an example). I would prefer to use AFP (Apple Filing Protocol).
Enable AFP from Web UI menu, Management, Application Management, AFT service. Click enable.
For Linux users, can enable NFS.
About performance of CIFS/SMB vs AFP, NSF can refer to here. If is not a few times different, I don't really care about which protocol to use. I just prefer to use the native protocol.
BitTorrent. This is another main reason (other than price), why I bought the DNS-320. I don't have to on my PC overnight to do the downloading, if I need to download a big image or software.
Bittorrent can be enable through Web UI menu, Applications, P2P downloads. Once you enable, the system will create a p2p directory under the volume. You can just drop your torrent file in p2p/Torrent directory. The bittorrent application will pick up the torrent file from the directory automatically. If it doesn't, just enable it from the web UI.
UPnP AV Server. Enable UPnP server turn the NAS into a media streaming server. Enable from Web UI menu, Management, Application Management, UPnP AV Server.
Use VLC (I am using version 2.x as example) to connect to the server to stream video file. Windows VLC menu, View, Playlist, Local Network, Universal Plug'n'Play. The media file on your NAS will be shown, it may take some time to refresh. You can play the media file or add to the VLC playlist.
Other features. I just cover 10 to 30 percent of the features. There are more to be explored, but the above already good enough for me, especially for a cheap and affordable solution.