>From personal experience I HIGHLY recommend disc mirroring.  15 minutes into my
new job here ldev 2 crashed.  We were down for the rest of the day (DDS-1 tape
drive...very slow).  The ironic part is I had to step around an HP 12H disc
array box that hadn't be setup yet.
Now that Y2K issues are slowing down I'm in the process of migrating from my 987
box to either a 989 or 997 with 6.0.  Should be a cake walk after what I've been
through.

--
Larry Barnes
Director of MIS
Mitek Corp.
4545 E. Baseline Rd.
Phoenix, AZ 85040
[log in to unmask]



"Costantino, Rocky" wrote:

> I have seen much more positive experiences, especially with regards to #1
> and #2. Disk mirroring improves read performance with the ability to read
> from the "least active" disk spindle.
>
> Regarding number 2, it doesn't matter which partner fails, the remaining
> drive will continue to service the disk requests, both read and write. Once
> the bad drive is replaced, which should be done as soon as possible, the new
> drive is synchronized with the REPLACEMIRRVOL command.
>
> I strongly encourage disk protection, whether it be MirrorDisk/iX or a disk
> array with RAID.
>
> Regards,
> >       _________________________________________
> >
> >       Rocky J. Costantino
> >       Vice President
> >
> >       Computer Design & Integration, LLC
> >       696 Route 46 West
> >       Teterboro, NJ 07608
> >
> > *     e-mail  [log in to unmask]
> > *     Web     http://www.cdillc.com
> > *     Phone   (201) 931-1420 x224
> > *     Fax             (201) 931-0101
> >
> >
>
> -----Original Message-----
> From: Rick Ingham [mailto:[log in to unmask]]
> Sent: Wednesday, January 19, 2000 10:50 PM
> Subject: Re: Mirror/iX
>
> Some observations based on my company's experience:
>
> 1) The software mirroring adds a 25% CPU load to all the process activity as
> additional overhead.
>
> 2) As often as it saves us, it also kills us.  Half the time the wrong drive
> of a mirrored pair goes off-line.  If the on-line drive is the one with
> errors, we have to reload the system, since it can't be re-sync'd nor can
> the other drive simply be switched on as the good one.
>
> 3) System reloads with morroring turned on significantly increases the
> reload/down time.
>
> 4) Reloading the system, then starting the resync, and letting users back on
> the system while the drives are resync'ing can cause another failure
> requiring again another reload.
>
> Bottom line:
> a) since the number of drives has doubled, the failure rate has also
> doubled.
> b) Doubling the failure rate and having Morroring fail to keep the system
> running properly half the time, means a net wash on reliablity.
> c) we have spent gobs of money on the extra drives, cabinets, SCSI cards.
>
> Net, we have paid HP an aweful lot for absoluty no benifit and a lot of
> headache.
>
> I'm trying to convince the powers that be to simply turn off the mirrors.
> "Rick Clark" <[log in to unmask]> wrote in message
> news:F4B1826B1A21D211AEC5006008207AF4043773CE@dogbert.csillc.com...
> > 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
> >