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Overview
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.
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The
Case
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! |
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The
Drives
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. |
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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. |
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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.
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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. |
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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. |
Tools
that we used
( I.E. you may want to use as well )
One note on power tools: use them at your own risk.
Be sure to read and understand any and all documentation
on the tools you use. No amount of documentation
can make up for experience, but there are many people
with serious eye injuries at the school of hard
knocks. If you don't know what you are doing, don't
do it and find some one that can help.
Tools
we used:
Dremel tool
Screwdrivers
Pliers
80MM Hole Saw
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