Poor Mans Raid Array
What self-respecting geek doesn’t get the warm fuzzies at the mere mention of the RAID. With the rising GB to Dollar ratio, we felt it was a good time to feature a project that takes Pure Geekieness(TM) and mixes in a good helping of do it your self. Where else are you going to store all those MP3s (legally obtained, of course)? On a single 200 GB Drive? Or a RAID 5 Array? Take you pick, I know where I will be storing mine.
RAID is defined as: “Redundant Array of Independent Disks”, but core geeks would probably prefer the definition to be more along the line of… “RAID Kicks Ass!” For about 250.00 we have made a true 0.5 terabyte RAID 5 array. What are the advantages of a RAID array? In short, data availability. Rather than having your (legally obtained) MP3 collection on a single drive, it redundantly spans multiple drives. in this implementation we will also be using a “hot ready” so that in the event that a drive did fail the RAID controller can shutdown the drive, and start rebuilding the array to the hot ready on the fly. We will also be covering a method that uses software RAID, and a USB based interface. Then you can paint it to look like a big iPod and make your friends all jealous.
In this build out there are really only a couple requirements for the case. It has to have the ability to house several (14) drives all at the same time, and must be able to power them as well. The drives we used are a little different than your home grown normal variety, they are taller than normal. So normal cases can’t fit them in the normal 1 inch tall bay. The solution is very easy with this case, with 2 support rails inside and the hole patterns on the rails for normal drive spacing, we will be suspending the drives inside the case so we can get the most amount of storage in the smallest amount of space. Also this is the first project we have done that takes advantage of the rackmount form factor. When it comes to lots of equipment in a small space this is the best way to go. Because Rackmount Kicks Ass!
So all geeking aside, for this project we choose the Seagate Barracuda SCA SCSI line of drives. There are several models you can choose from, the “ST118273LC” 18.6 GB drive is readily available on eBay for about $5.00 a drive, or the “ST150176LC” 50.1 GB at about $15.00 each. I was fortunate enough to get a “Bulk Lot” of the 50 GB model for about $70.00. These drives can run very hot, and do require alot of cooling, so we will be modifying the case to improve airflow and keep the drives cool.
SCA to 68 pin SCSI Adapters
This is a really simple but critical part of the whole processes of this build. The drives we got are SCSI, but with a unique plug on the drive. Most SCSI devices can be converted, or adapted to other types, I.E. SCSI I to SCSI II. For this project we will be using the SCSI II interface for our cabling, and adapters and raid controller. Additionally, most SCA drives (like the ones we are using) don’t allow you to set the ID on the drive itself. The adapter has a bunch of jumpers that allows you to assign the drive a unique ID number up to 16 ID’s total with this particular adapter. They are readily available on eBay or from other online SCSI equipment vendors. They can be found from $2.00 – $8.00 each. We got ours for $4.00 each.
The Fan Array:
Heat is always a concern with any computer equipment. But here there are a few special concerns. The drives are all 10K RPM. So they run hotter than usual drives. In fact when idle they produce about 20.85 BTUs. When active they average about 71.2 BTUs! Factor in the fact that RAID solutions are usually about 25% more intense on hard drives, and that we have 14 of these drives in a single case and you can see why we have a potential problem with heat. Up to 996.8 BTUs for the array total! Another concern is that as a drive heats up it can actually affect the drive enough that it doesn’t write data consistently as the platters heat up and change shape. Personally I really hate hot platters, like the ones at Chili’s… I always get burned. So to handle this issue, we have come up with a custom fan array to whisk the air and heat away from those ever so expensive drives.
SCSI Raid Controler ( IBM ):
I’m a big fan of using the older technologies in more modern uses. The problem is that many companies like IBM have a habit of killing support for drivers. This is where my love for Linux comes in. I have yet to find an older RAID controller that doesn’t have drivers for Linux. So naturally with this in mind I went shopping for some good RAID controllers. The one I found that really stood above the rest was the IBM Server Ultra II RAID Controller model “76H3587″. This unit has 3 separate SCSI channels on it, supporting 16 devices per channel. Linux is totally friendly with it, and they sell on eBay consistently for about 11.00. The raid features on this card are really nice, good interface and setup for your arrays. It allows for the hot spare we all love and want oh so badly… well maybe just me.
Now, where is my hammer.
The project really centers around the right case. The case we are using I get and use frequently at my place of employment. The vendor we use for these cases is a local group called EBC Computers. Who knows what EBC stands for, this is not a plug for them, it’s just the only vendor for this case I have found…. any who the part number is CA-TT-R19-B-320 with them. The box is labeled with the brand IPC, but I have yet to find a similar case with the rails like this case has.
So what makes this case so special? The structural rails running from left to right as you see here. The rails are designed with the option of handing drives, or cooling fans from them. No other case I have found has 2 rails in them. Many have one rail. The second here is a bit of a scarcity. So now all we need to do is get rid of all the crap we don’t need. Be sure to save the odd bits for future projects.
The case is as empty as a Comdex convention without the Microsoft booth’s go go girls… we really removed everything we could here. The front fan plates, and fan, the drives, drive housing, the floppy housing, the hard drive mounts, speakers, the rear panel, and the motherboard mounting plate. Everything we could. With the case stripped you can really see just how much room we really have to work with in this case. There is alot more room for alot more drives if you used regular form factor drives in this mod. But that’s not what was doing here now is it….