[K12OSN] Hard Drive Upgrade Quandry

[Liam Marshall]

we are skating on the edge of being too low on hard drive space.  With 
careful management of the ltsp environment I think we could make do but 
there are several reasons I don't want to.

1.   First, in most cases I am a believer in more is better, hardware 
wise.  What we have for hard drive space is 27 GB total.

2.   Our current hard drives are composed of old, slow (5400 rpm, cache 
?) scsi harddrives 1 9GB IBM and 1 18GB Seagate.  They are both hooked 
in through a decent but non raid adaptec controller with no upgrade path 
for it

3.   With our current setup we have zero redundancy.  I have /home and 
/opt as well as the swap partition on the 18GB seagate and /root and the 
rest on the 9GB IBM.  If either goes down I am well and truly screwed.  
and deservedly so with no redundancy. But I wanted to prove the LTSP 
idea to the school and did so by creating the server out of mostly used 
parts.  Money will forever be the ban of school computer labs!

Anyway, long story short.  The board is impressed enough to spring loose 
some money for hard drive upgrade, maybe over the Christmas holiday.

I was considering the following in an effort to save some money.  Let me 
know what you think of this setup.  Remember that the current setup up I 
am using is old slow scsi drives and that it is working sufficiently 
well performance wise


I would like to get a Promise IDE raid controller, either the 4 or 6 
channel version, haven't decided yet.  I was going to put on it 4 - 80 
GB EIDE hard drives with 7200 rpm and 8MB cache each.  I would use these 
in a raid 0+1 or raid 1+0 configuration.  It is my understanding that 
this will give me the best of both mirroring for redundancy, and 
parity/spanning for performance.

If I am right in my understanding of raid levels 4 - 80GB drives in such 
a configuration will give me 160GB of storage space, with the other 
160GB of the drives being used in a mirrored capacity right?

Opinions?  Comments? 

I am leaning with EIDE solution because of price vis a vis scsi and 
because sata really isn't available in my area yet and is still fairly 
expensive/unsupported?

Opinions?  Comments?