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How to Build Your Own 1U Rack Mount Server and Save a Bundle

Jan 16, 2000, 06:58 (76 Talkback[s])
(Other stories by Tom Adelstein)

By Tom Adelstein

News item: Chassis manufacturers and distributors from North America to Taipei can not keep up with demand for 1U rack mount enclosures. Any quantity orders made today will ship in late March.

The rush on thin rack mount chassis servers with a Linux operating system seems remarkable. The engineers at Cobalt Networks (NASDAQ:COBT) pointed the world to a computer that could stack 42 systems high on a standard rack. Now, people have made this the latest computer craze. First, ISPs and people with limited rack space created the basis for a market. Soon, people began to see the advantage of the smaller form factor in everyday computer life.

This article should take the mystery out of the 1U rack mount computer and allow you to build your own. Of course, you have to decide if buying a pre-built model serves your needs. Many Linux users prefer to build their own systems and those who don't have many manufacturers from whom to chose.

You might discover that finding a supplier of the small chassis as the most difficult part of your project. So, we can make this much easier for you. The people at General Technics ( sell their IPC Case 3 Bay 1U ATX 150W [Beige] chasis for $268. This may seem a bit pricy compared to the $79 conventional case. Considering supply, demand and what other distributors charge, General Technics (GT) provides a high quality case with a single riser card for the lowest price we have found.

GT calls their case the CS 440. The dimensions make this chassis a tight fit and you'll soon discover you'll need a special motherboard and accessories. The height is only 1.75 inches while the CS440 case itself is about 17 wide and 22.5 inches deep. The distributor pegs the weight at 21 pounds.

The most popular motherboard for the 1U rack belongs to Intel. A standard Intel Brand CA 810 board will provide you with ample resources. Fry's sells the Celeron only version for $119. Many people buy the Intel Pentium III board which Fry's sells for $149. I like the lower priced motherboard because I don't see much performace difference between the Celeron and the Pentium III for my server needs. Staying with the Celeron also saves you money.

The stock CA810 doesn't come with a Network Interface Card. Intel offers an optional 10-100BaseT ethernet card on board in the CA810LA. You may want to pass on that option in favor of the Intel® PRO/100+ Dual Port Server Adapter (PILA8472 DPA).

The 1U case has room for one riser card which fits a standard PCI slot. The card makes a right angle which allows for one peripheral device. Using Intel's PILA8472 DPA allows you to have two adapters in the same space. The cost of the DPA can run between $200 and $300 depending on how and where you buy. If you only need a single ethernet port, 10/100 cards support by Linux can run as low as $20.

Once you decide on your ethernet card, you'll need a processor, memory and a hard drive. One popular choice is the Celeron 500MHZ 128K L2-cache PGA-370 which comes with a 3 year warranty. The PGA-370 has a flat form factor similar to the original Pentiums which fit into a Ziff socket. The Celeron and Pentium III processors both come in PGA-370 form. The current price for the Celeron 500 runs approximately $135 with a cooling fan. You'll need a low profile fan for two reasons. First, a standard fan would exceed the 1.75 inch height of the 1U case. Secondly, even if one modified an existing fan, it might clear the 1.75 inch height but without clearance. This would cause the fan to pull air and speed up similarly to when you put your hand over a vacuum cleaner hose. The heat generated from the air suction on the processor fan would cause the processor and components to fail. Make sure your cooling fan has enough clearance to turn freely and circulate air normally.

Memory prices seem to change every day. The Intel CA810 board has two 168 pin dimm slots. You can run up to 512 MB of RAM. Even so, you need to buy low profile memory since a standard 168 pin dimm mounted on the motherboard exceeds the 1.75 inch height of the case. Expect to spend about $160 for the 128 MB of memory and $80 for 64 MB.

The price of hard drives has come down rapidly over the past two years. Recently, I bought a new 13 GB Maxtor 5400 rpms ultra dma hard drive for $125 at a local computer mega store. You will find that prices vary on hard drives and if you take your time, you'll find a high performance drive in the $100 -200 price range.

The 1U rack mount server described above uses a standard ATX form factor, mounting hardware and power supply. The motherboard installs easily as will the other components. (see How-to Build a Low Cost Linux PC). Your only other choices involve whether or not to install a floppy and a CD Rom drive.

The CS 440 rack mount chassis accomodates a single standard ATAPI CD Rom and a single floppy disk drive. The cost of devices should run approximately $20 for the floppy and $50 for the CD Rom. The convenience of having either or both of these devices is well worth the cost.

Let's compare the cost of our 1U Rack Server to several name brand systems configured in the $1200 to $1500 range. We'll use a Celeron 466 MHZ processor to make the systems compataible. You can see the costs summarized in the table below.

CS 440 1U Rack Mount Chasis $268
Intel CA810 Motherboard 119
Intel Celeron 466 MHZ processor 85
Single Port Adapter 20
64 MB DIMM 80
13 MB Hard Drive 125
CD Rom and Floppy add $75 (Optional) -0-
Total $697

Since this is a Linux system, we can obtain almost any Linux distribution for free. If you feel comfortable with remote administration via OpenSSH, then you're done. If you don't worry about security, you can use telnet and ftp which are standard UNIX tools for administration.

In the event you plan to co-locate your server at an ISP or in another remote location, you may want to consider pre-configured software from NetMax. For approximately $80, you can buy off-the-shelf Linux server packages at most retail computer stores. Web enabled software such as NetMax's Web Server gives you the advantage of remote administration through a web browser. So, for less than $800, you can build something similar to a RaQ2 running Intel packages. This gives you greater flexibility in configuring your server for about 40% of the cost of a comparable system.

The mystery of the 1U Rack Mount Server lies in its height restrictions. Use low profile memory, the CA810 Intel or comparable motherboard, and PGA 370 Ziff socket (Celeron or Pentium III) processors with low profile fans. If you understand the height restriction, the IU server configures like most any other generic PC.

Tom Adelstein, CPA, is the CIO/CFO of Bynari, Inc. He's the author of several books and articles on business and technology and has management, consulting and hands-on experience in the Information Technology field.