On Thu, Jan 21, 1999 at 10:28:23PM -0500, Robert Adams wrote:
> We're putting together a new box to handle mail.. thought I would pick your
> brains a little for advice. Hopefully someone has done this already.
>
> We are planning on using 4x9gig Cheetahs in a RAID 0+1 configuration..
> Currently we are looking at two RAID-RAID controllers.
>
> 1) Mylex 2 CHANNEL RAID W-U SCSI DACSXI
> 2) CMD CRD-5440 or CRD-5500's
1) RAID 0+1 is creating two stripes, and mirroring one onto another.
RAID 1+0 is mirroring each drive to another, and striping across
the resulting volumes.
They aren't the same thing. Really. They aren't.
with 0+1, the second drive you lose results in the loss of the data.
with 1+0, you can lose one drive from each mirrored pair, and still
maintain data integrity. It's the no-compromise approach to RAID
sets.
> Few questions.. can anyone recommend one of the above controllers over the
> other? If so, for what reasons. Does the RAID 0+1 seem like the way to go?
> Or should we go with something like RAID 5?
Pound on the sales people and inside tech people at the companies you're
deciding between. I don't know of any Mylex RAID controllers which allow
1+0, but that doesn't mean they don't have one. I know that CMD has a
controller which allows 1+0, but I don't know that you're looking at it.
It's up to you to make sure you're spec'ing the correct hardware capabilities.
RAID 5 has slow writes which make it unadvisable for data that undergoes
updates on a minute to minute basis.
> The reason we aren't going with something like the DPT controllers is that
> you have to boot to DOS to fix a failure... which isn't good imho. Any other
> controller/setup recommendations are welcome..
Personally, I'm not into server controller based RAID. I'd rather have
the RAID look like a drive on the SCSI bus...
--
John White
[EMAIL PROTECTED]
PGP Public Key: http://www.triceratops.com/john/public-key.pgp
