Although asked for a private reply but seeing the response of [log in to unmask]
I couldn't resist to answer public.

We use Mirror/iX since several years to overcome performance problems on our
business critical 995-800 and 995-500.
The 2 GB SCSI Disks in place (2* 50 pieces rsp. 2* 25 pieces) served by several
SCSI Interface cards plus Mirror/iX did this perfectly - the Disc I/O
bottlenecks disappeared for the most heavily used database/account serving the
Order Fullfillment Process for DuPont.
The server itself benefit from this action as well ... I can not give you an
exact number but the paused time was reduced because of eliminating the Disc
bottleneck. Basically, the Mirror/iX process itself was not recognized as an
additional overhead.
I cannot understand what rdingham means when he says "the wrong drive ... goes
off-line". In a mirrored environment, you have identical information on both
drives so that you can read in parallel on two locations but the writes will
happen in parallel to two places as well. If one drive will fail, the other will
take over and, I admit, from this time on you have a single point of failure: if
this will fail as well, you have to perform a RELOAD of this volume set.
We also had to perform several reloads in re-shuffling discs between the volume
sets - but also this action didn't take longer than before.
We had only three defect drives in the last years, and we never had to reload
the system / volume set because of this repair. And NEVER the 2nd disc failed
when we had such a single point of failure.

So, from our perspective, we can say
* Mirror/iX is a cheap solution compared with Disc Arrays to ensure a high
availability on business critical servers,
* the SCSI drives & interfaces are very reliable,
* the repair process (if needed) is proven and straight forward.

May I point you to an article which was published in the 3000 Newswire? It's
called
"How to Deal with Mirrored Disks" (sept. 1999) and is available either on the
3000 Newswire site or on http://www.hillschmidt.de/gbr/
Click on Published Articles, and select this one. I admit I wrote this stuff ;-)

Hope this will give you (and others) another perception on Mirror/iX.

Best regards, Andreas Schmidt, CSC, Germany





[log in to unmask] on 19/01/2000 10:17:26 PM

Please respond to [log in to unmask]

To:   [log in to unmask]
cc:    (bcc: Andreas Schmidt/GIS/CSC)
Subject:  Mirror/iX



I thought I remember a while back an article in one of the HP trade mags
that described the process of installation and configuration of HP's
Mirrored/iX. Anyone remember such an article and could they point me to
where I can find a copy? Thanks in advance. Please reply privately.


Rick Clark
Senior Systems Analyst
WW&R
Cleveland, Ohio