Build Your Own
There is another solution that is cheaper and offers significantly more flexibility: building your own file server. And there is no reason you can't build your own, just as enthusiasts regularly build their own computers instead of buying pre-built machines.
Of course, there are many decisions to make when building your file server. A few of the most important are how much data you want to store, how much redundancy you require, and how many disks you plan to use. If you want to house lots of information, I recommend minimizing cost per gigabyte rather than buying the biggest drives available. Today, the best value falls around the 1 TB range. I personally like RAID 5 because it can tolerate the failure of a single hard drive. If you are going to use more than eight or 10 drives, you probably should build multiple RAID 5 arrays with four or five hard drives each or use RAID 6 to shield against the failure of more than a single disk.
Enclosure And Storing Disks
You will have to buy an enclosure big enough to house all of your hard drives. If you buy an enclosure that is too small, you can always switch to a larger one later on.
The enclosure will need to keep all the hard drives reasonably cool. There are many enclosures that offer decent cooling. For my first file server, I used a generic no-name case. Its best feature was a 120 mm fan in front of the hard drive rack and a 120 mm exhaust fan. I added a Cooler Master 4-in-3 module with a dedicated 120 mm fan to cool the hard drives. This is a great way to hold hard drives. The only downside is you have to remove the whole module to change a single disk.
For my second file server, I selected two Supermicro hot-swap SATA hard drive racks, each holding five hard drives. They were much more expensive than the Cooler Master drive holder, but also have more features. The second enclosure uses a very loud 92 mm fan (which I slowed down with a fan controller), sounds an alarm if the fan fails or the temperature gets too high, and shows disk access for each drive. Best of all, you can change hard drives without opening the case, and if the operating system supports it, without even turning off the computer.
You will want a Gigabit Ethernet interface for your file server to help speed up data transfer rates. You will likely use jumbo packets, so make sure your Ethernet switch and onboard controller supports jumbo frames (most new devices do).
Ethernet originally was specified to have a maximum payload size of 1,500 bytes. This was plenty when the technology ran at 10 Mb/s. When Gigabit Ethernet was introduced, the overhead associated with small packets became significant. The industry had a de-facto agreement to support larger payloads, and 9,000 bytes is the size that was picked. This means you can transmit the same amount of data as if you were using standard-sized packets, but with a six-fold decrease in packets and six times less overhead.
In practice, you will save CPU cycles and see increased throughput using jumbo frames if the network is a limiting factor when transferring data. If you do get a switch that doesn’t support jumbo frames, it might get confused and not pass the packets, so you should disable the feature if you have a switch that doesn’t support it.
You can get an eight-port switch for about $40. Most modern motherboards have Gigabit Ethernet connectivity onboard, but on the off chance that your motherboard does not support it, get a PCI-X or PCI Express (PCIe) card instead of a 32-bit PCI card. I have had good success with Intel’s and Broadcom’s PCI-X Ethernet cards.