TeraServer Project – Part 2

Choosing RAID configuration means deciding on priorities – which is more important: available disk space or failure recovery? In a production system I would choose differently, but for a home server, having bought four disks, I wanted to maximize the storage potential by using the facilities of RAID to combine the disks into one volume (it is a TeraServer after all!). I also wanted to get some of the benefit of RAID failure checking and recovery – it would be storing all my important files (yes, I have backups too). In the end I decided to allow for 1 drive failure to maximize volume, and settled on a RAID-3 configuration. In the end, after building the RAID array, mounting it as a Linux volume, and allowing space for system partitions and Linux files, I was left with about 825GB for storage.

So with the arrival of the SCSI disks and Adaptec SCSI RAID card, I could begin.

Getting the RAID caddy into the case was fairly easy. I just cut out some portions of the metal front plate, and the caddy slotted into the chassis four-bay drive frame perfectly. Good choice.

One thing I was keen to try on this project was to add a cool front status display. There was just enough room on the case below the drive bay to fix a 4-row backlight LCD display. Next to it, a recessed power button. Finally, I added a new plastic front-plate, cut to fit the custom parts and sprayed the whole thing black and the case externals were done.

TerraServer_4_CaseModsCompleted

The internal space was – tight! There was plenty of room at the back, behind the drive bay above the mainboard, but the mainboard runs some of the way underneath the drive bay. This left some contact between the SCSI card and the RAID caddy. Some precautionary insulation of the bottom of the RAID caddy with electrical tape solved that problem. I also added some sound baffling and insulation around the top of the RAID caddy.

Another issue was the LPT connector on the board. This was how the LCD display module needed to be connected to the mainboard. Clearance was tight for the LPT connector, but the bigger issue was making the internal! I bought a standard shielded parallel cable, cut it, and armed with some veroboard, a soldering iron, LPT pinouts and the HP LCD module tech sheet I had a custom parallel cable made!

TerraServer_5_CompletedInternal

TerraServer_6_CompletedInternal2

With all the hardware done, it was time to install the OS. I wanted a stable server distro, so opted for CentOS Linux. The install process picked up the correct drivers (I just had to provide the Adaptec storage driver). I installed Samba to share out the drives, VNC server to connect to administer it (local subnet access only), and I had my TeraServer! The trickiest part was getting the LCD display to work. Parallel ports are rarely used anymore. With a bit of research I found an open-source lpt driver to install. Finally, configuring and installing LCDproc for my display module gave me a server that really looked like it means business.

TerraServer_7_@home

$1000 less than buying one, and all the fun of the build too!

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