[plug] RAID Setup

[Fred Janon]

Personally I like mirroring, simpler and faster than RAID 5. Striping
gives speed, depending on how it's done and what you do. I also agree
with you with doubling the configuration, eliminating the single point
of failure if connected to 2 different controllers, although then the
single point of failure becomes the computer they are connected to.

The main problem in using ATA (unless things have changed over the last
couple of years) is that ATA bus doesn't allow disconnection (unlike
the SCSI bus and I think now SATA). To achieve performance with ATA
drive, you need as many ATA buses as you can get to get a bunch of
drives active at the same time.

Fred

--- Phillip Bennett <phillip at mve.com> wrote:

> 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.
> 
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