For System Builders...

Assemble a custom Media Server with up to 38TB of protected storage!

Start out by downloading unRAID Server for free! Unregistered unRAID Server supports up to 3 hard drives. 

Component Selection

unRAID Server will run on a large range of hardware configurations.  For a basic system, you could make use of PC hardware you might have laying around.  For a larger server, component selection becomes more important.  To support more hard drives and additional functionality, you may purchase a Registration Key.

The remainder of this article describes component selection for the MD-1510 Server.

Form Factor

The first decision to make is the size of your server.  For a large capacity tower-style server, there are two choices: mid-tower or full-tower.  A full-tower server with 12 5.25" bays offers the most potential storage space, since 4 5-in-3 hard drive cages may be installed, supporting up to 20 hard drives.

The main disadvantage of a full-tower chassis is it's sheer size and weight.  For this reason, a high quality mid-tower chassis that can support 15 hard drives was selected for the MD-1510 Server.

Drive Cages

So-called 5-in-3 or 4-in-3 or 3-in-2 hard drive cages may be used to simplify installation of hard drives.  The X-in-Y designation describes how many hard drives (X) can be fitted into how many 5.25" bays (Y).  The highest storage density is achieved with the 5-in-3 cages.

There are many choices when it comes to drive cages, and we have evaluated nearly every model out there.  Our conclusion is that Supermicro makes the highest quality drive cages.  The CSE-M35T-1B 5-in-3 drive cages are very solid and have good fans.  They are not perfect however, with these disadvantages:

• Being made of steel, there are heavy.
• The fan is very noisy (though considerably quieter when slowed down via fan controller).

The next best drive cage is made by IcyDock.  These cages are made of aluminum so they are lighter.  Since aluminum also dissipates heat better, the IcyDock fans are smaller and run slower, hence much quieter than Supermicro.  Disadvantage with IcyDock is, since it's made of aluminum, cages are also less "solid".

Forget Drive Cages

It's also completely viable to not use drive cages at all if you don't mind dealing with power and data cables every time you want to install or remove a hard drive.

Motherboard, CPU, RAM

The primary consideration for motherboard choice is the number of on-board SATA ports, and the expansion possibilities for adding SATA controller cards (to get more ports).  The MD-1510 uses the Supermicro C2SEE/C2SEA motherboard with 6 on-board ports.

There are many motherboards on the market which include 6 on-board SATA ports, but the C2SEE/C2SEA also includes three PCI-Express slots, two of which are capable of PCI-E x4 operation.  This is important because we use PCI-E disk controllers which operate at PCI-E x4 speeds.

Other considerations in motherboard selection include:

• On-board GigEthernet.  This is important; you won't be happy with only Fast Ethernet (100Mbit).
• On-board video.  You need video to configure your bios and provide a console.  You could also just install a cheap VGA controller.
• Operating system bootable from USB Flash.  These days, virtually all motherboards support this capability.  One rule of thumb: if the motherboard includes on-board GigEthernet, then it's probably new enough to support USB boot.

One other nice feature of the C2SEE/C2SEA worth mentioning: it includes a female USB port mounted right on the motherboard.  This lets you easily install your unRAID Server Flash device internally.

CPU & RAM

Just about any CPU is powerful enough to run unRAID Server.  In a media server application, the bottleneck lies in the bus speed (where PCI-E is far faster than PCI), and disk speed.  If you will be running other server applications, then it might be advantageous to use a more powerful processor.

Similarly, RAM speed makes little difference as long as you are running dual-port.  So make sure you get two sticks of RAM, one for channel A and one for channel B.

Hard Drive Controllers

Since peripheral bus speed quickly becomes a bottleneck for parity sync/check, if parity sync/check speed is important to you, try to use PCI-E disk controllers.  The MD-1510 uses Adaptec 1430SA controllers which operate at PCI-E x4 speeds.  After booting your server for the first time, be sure to enter the Adaptec bios and set it up to disable it's on-board RAID bios; this will cause the card to operate in JBOD mode.

Forget PCI-E

For a less expensive solution, you can use PCI disk controllers.  Your parity sync/check speed will not be as fast, but all other normal operations (read/write of media data) will be just as fast.  Since parity sync/check can be done during times when your server is not being used, parity sync/check speed is less important.

Power Supply

Last, but certainly not least, is power supply selection.  In a media storage server, almost all the power is being used by the hard drives.  For this reason, it's very important to use a single +12V rail design.  This is because split-rail designs will not direct full power to the peripheral connectors used by the hard drives.  There is a good article on the PC Power & Cooling website that discusses this further.

Finally, do not use a cheap power supply!  Spend your money and get the highest quality, single-rail power supply you can find.  Many obscure, intermittent hard disk problems may appear as you add hard drives in a system with a cheap power supply.  You have been warned!