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Date:      Sat, 31 Jan 1998 14:46:04 -0600
From:      Karl Denninger  <karl@mcs.net>
To:        Brian Tao <taob@nbc.netcom.ca>
Cc:        current@FreeBSD.ORG
Subject:   Re: RAID controllers - folks, check this thing out
Message-ID:  <19980131144604.03410@mcs.net>
In-Reply-To: <19980131143250.22533@mcs.net>; from Karl Denninger on Sat, Jan 31, 1998 at 02:32:50PM -0600
References:  <19980130233604.57426@mcs.net> <Pine.GSO.3.95.980131150738.27817Y-100000@tor-adm1> <19980131143250.22533@mcs.net>

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On Sat, Jan 31, 1998 at 02:32:50PM -0600, Karl Denninger wrote:
> On Sat, Jan 31, 1998 at 03:17:52PM -0500, Brian Tao wrote:
> > On Fri, 30 Jan 1998, Karl Denninger wrote:
> > > 
> > > Talk to Pacific Computer Expansions, a gentleman by the name of
> > > Warren at 800-458-5058.
> > > 
> > > You want the CRD-5440.  
> > 
> >     This is the CMD product (http://www.cmd.com/), isn't it?  I had
> > one of these from Open Storage Solutions (it's their "Infinity RAID"
> > product) on a FreeBSD box in 1996.  If you search for the string "CMD
> > and RAIDION" in the freebsd-scsi archives, you'll find some of my
> > benchmark reports on the CRD-5500.
> > -- 
> > Brian Tao (BT300, taob@netcom.ca)
> > "Though this be madness, yet there is method in't"
> > 
> 
> CMD makes several products.  This is their newest architecture.

CCD mounted async is NOT a fair comparison - not at all.

CCD mounted *normal* might be close to a fair comparison.

Also, RAID 5 with other than 5 disks is sub-optimal, and some of those
tests were run with fewer drives.

I've discovered that the CMD controller here has switched three of the 
five disks down one notch to 10/20Mbps transfers (from 20/40).  It is 
not completely happy with the cable arrangement, obviously.  I will fix 
that Monday and see what that does for performance.

As a result, my tests so far are running with half the disks at only
half of the proper transfer rate!

--
-- 
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