The home media server

What's a home media server? A central place to put all that data you have, from e-mail to music to movies. With multiple PCs becoming commonplace in the home, the need to push data through every room in the house via Ethernet or WiFi combined with the proliferation of digital-only content mean the storage demands of home users are rising quickly.

Fortunately, hard drives have been getting cheaper as well, to the point where they are treated as commodity items by OEMs and even smaller system builders. The major upside of this is that storing 250GB of data or more can be done for well under $100, and 500GB for $140. Compared to prices 10 or 15 years ago of $1 per megabyte, and the possibility of a home media server with a terabyte or three of storage is sure to bring a silly grin to many a face. A cheap home PC can store a few hundred gigabytes of data very cheaply, while a low-cost home media server can rack together a few hard drives to act as a central location for data storage, distributing everything over the home network.

For our first Home Media Server guide, we're including two options: Budget Media Server and the Performance Media Server. For the most part, the parts are interchangeable between the two so you can mix and match the components to meet your needs.

The economical Budget Media Server is possible with the presence of on-board RAID on most motherboards today. All but the cheapest motherboards and chipsets today implement some form of RAID, and they come with 4 or more SATA ports to allow a 4-disk RAID array to be done with no additional equipment on the end user's part. While the most basic forms of RAID supported are striping (RAID0) and mirroring (RAID1), spending a few dollars more on a motherboard built with a chipset that supports RAID5 (striping with distributed parity) allows users to build a modestly fault-tolerant cluster of hard drives while sacrificing only a single drive's worth of storage space. Performance and reliability are not going to win awards, but for a home media server, the modest performance of onboard RAID5 is more than enough.

The Performance Media Server adds quite a bit of performance and expansion potential. While it is probably overkill for the home, people whose storage needs are this large probably enjoy having overkill. Going to a true hardware-based RAID controller from Adaptec, Areca, LSI Logic, 3ware, or a similar company with high-end features such as online capacity expansion and gives a significant performance increase and easy support for much larger numbers of drives and arrays. Most motherboards top out at 6 SATA ports, while a hardware RAID card may have as many as 24 SATA ports. The Performance Media Server also adds more memory and a faster processor, allowing it to easily handle encoding and decoding tasks, allowing the removal of heavy tasks from the desktop, which can then spend more time helping you play the latest MMORPG.

RAID means what?

Note: a full discussion of RAID concepts is beyond the scope of this guide, but you can check out "The skinny on RAID," which will educate you on the whys and wherefores of RAID.

As far as the Media Servers are concerned, RAID is an easy way to make multiple drives appear as a single one. The danger with multiple hard drives ganged together to appear as a single large drive is that the failure of a single disk could result in the loss of data in the entire array.

To reduce this risk, most levels of RAID (except RAID0) include some form of mirroring (RAID1) or parity (RAID5, RAID6, etc.) to protect against drive failure. The most inexpensive form of RAID in the balance of space-vs-reliablity is RAID5, which uses a single drive's worth of space dedicated to parity data. This results in an array that can sustain only a single drive failure, but with the relatively low stress seen in home media servers, fault tolerance for a single disk failure should be adequate, and the relatively minimal cost of lost space means that small arrays can maximize their remaining capacity.

RAID5 is not ideal for everyone or everything, but in a small array with four or six drives, losing only a single disk's worth of storage is seen by many lightweight users as a good compromise than losing half the disks' worth of storage to the most common form of redundancy in a RAID array, RAID1.

Hidden costs

Four disks at 500GB each is 2TB, six disks is 3TB. Going to 750GB disks gets 3TB with just four disks, but at double the cost per disk.

Reality is rarely that simple. The money saved by buying smaller, cheaper disks is offset by the fact that they still have to be connected to the RAID controller, powered by the power supply, and cooled by the fans in the chassis. Most motherboards and RAID controllers have four ports. Going to six disks rather than four suddenly means you need a separate controller card—or you'll have to hunt for the rare motherboard with six SATA ports. A hard drive consumes 15 to 20 watts of power when actively seeking, which may mean you'll need a bigger power supply, and then you have to find a case that can fit more disks. Finding a case capable of holding four or five 3.5" drives is not overly difficult, but think six or eight disks and the task becomes, if not more difficult, then at least somewhat more costly.

It's a balancing act. Throwing future expansion into the mix only complicates things.

Another important issue is noise. Putting lots of hard drives together in a small space tends to lead to lots of noise and heat. Fans to circulate the air from very tightly packed components tend to be of the high-speed, high-flow variety by necessity rather than by choice.

Building a low-noise or even a quiet media server is difficult but not impossible. Large heatsinks with low-noise fans, low-noise case fans, passive coolers for chipsets, and low-noise power supplies as found in the regular Ars System Guide, particularly the Hot Rod, may aid in the goal of a low-noise media server.

Balancing noise versus cooling needs and cost is not easy. While we try to avoid specifying loud components in the Media Server guide, we recognize the fact that these boxes are not going to be particularly quiet.

Budget or Performance?

With a home media server unable to ever take full advantage of a fast RAID controller, the real breakdown between the Budget Media Server and the Performance Media Server is expansion potential. Cramming another disk or so into the Budget Media Server is about the limit of the motherboard and the chassis. The Performance Media Server can handle additional drives more easily. With a larger starting budget, initial capacity can be much greater while retaining significant expansion potential.

From the price of each configuration, the cost to support more than four or so drives increases quickly. The Budget builder recognizes this limitation, while the Prformance builder can both justify the additional capacity and afford to spend the money. It's up to the individual reader to determine what suits his or her needs best.