[Scottish] RAID Setup

[Phillip Bennett]

Hi everyone,

I'm looking into building a RAID setup for our new Virtual Machine host. 
I'm trying to condense around 4 or so servers into one box with Xen, using 
ATA over Ethernet as the storage solution.

I've found a great case and setup to use (via http://xenaoe.org) that houses 
15 drives.  I can fill it up for very little cost, but then I'm wondering 
what kind of RAID to use...  We don't have huge space demands and I'm sure 
anything will be faster than our current storage solution.  However, I 
*would* like some decent speed and redundancy.

So: How would you set something like this up?  RAID5, or maybe some groups 
of RAID0+1 or RAID 1+0?  What would give me the best speed as well as 
resiliancy?

I was thinking of starting with 15 disks, using two for hot spares, leaving 
13 disks between 2 RAID sets - one of 8 and one of 5 disks.  The smaller set 
would be RAID5 and used to host the virtual machine images and some less 
used files (PC images, drivers etc..) and the larger set would be for our 
company data.  I'm just at a loss for how to do it best.  At the price I can 
get the parts, I was actually thinking of mirroring the 15 disk enclosure 
entirely (ie Software RAID1) to shut the boss up about a single point of 
failure.

Does anyone see any problems with this or have any suggestions?

Thanks in advance,
Phil.