The D-Link DNS-321 is among the least expensive dual-disk RAID NAS systems currently on the market. This small device offers an impressive array of features such as FTP, Samba, NFS, iTunes, DHCP, HTTP and UPnP servers, user and group access management, several RAID levels, a well-designed Web interface and gigabit network support. It is this last feature that I would like to discuss in some depth.
Those of you who are not computer experts need to understand this: the DNS-321 is not just a small black box with two hard drives but an actual computer that has it’s own CPU, memory and operating system. If, looking at the DNS-321′s small size and low price, you were to imagine that it is not a very powerful computer, you would be absolutely correct. And there lies this gadget’s only major flaw.
When originally designed, DNS-321′s predecessor was intended for wireless or 100Mbps networks. The device’s CPU and other system resources were precisely scaled to cope with 100Mbps (12.5 Megabytes per second) data transfer rate. This was necessary to provide the desired performance and features, while keeping the device as affordable as possible.
As time went on and gigabit (125 Megabytes per second) networks became more common in small offices and homes, D-Link’s marketing folks must have felt an unbearable urge to include gigabit support in their low-end NAS products. The hardware was upgraded to include a new integrated gigabit network interface.
If you connect the DNS-321 to a gigabit network, true to the claim on it’s packaging, the gadget will establish a gigabit link to your network. Unfortunately, painting racing stripes on your old rusty Ford Tempo does not turn it into a supercar. Running FTP, NFS, Samba, UPnP and other services supported by DNS-321 requires processing power and a certain amount of memory. These requirements grow with the rate of data transfer.
Unfortunately, DNS-321 has just enough resources to comfortably handle up to about 14.5 MB/s, which is a long way from the maximum transfer rate of a gigabit network. Thus, D-Link DNS-321 is a NAS system capable of establishing a gigabit network connection but not capable of using it. What do they say about having your cake and eating it? Not for a hundred bucks, my friends.
If you already own the DNS-321 and would like to get the most performance out of it, there are a couple of things you can do. First, you will need to upgrade the firmware to the latest version. Most DNS-321 units shipped without NFS server functionality, which has been added in the later firmware version. The upgrade is performed via the Web interface and the entire process was quick and painless. Turn off services you are not going to use, such as DHCP and UPnP, for example. Doing so will free up some valuable system resources and will slightly boost data transfer speed. Avoid using Samba – it is a resource hog. You will get at least 20% faster transfer rate using FTP or NFS instead of Samba. Unfortunately, there is no way to disable the Samba server. The speed offered by the DNS-321 is entirely adequate for playing uncompressed videos in 1080p resolution with a DTS 5.1 audio track. I’ve been streaming a 40GB MKV file via NFS to an XBMC player without any issues. However, as a file backup solution the DNS-321 is just too slow for my liking.