Mark,

     We have been using Disc Mirroring and Auto Restart together on over
     half of our systems for over a year now.  All of our production
     systems will be using it very soon. It does work great! It is easy to
     setup/install.

     Depending on the size of your production data, recovery time could
     become next to non existent if a mirrored drive fails. Meaning you
     would be able to 'schedule' disc drive replacements. This is all
     transparent to your users. If you 'were' to experience data loss on
     the mirrored 'private volume set', you only have to 'reload' that
     private volume set. Reducing reload time to a few hours instead of all
     day. Here at Cardinal we can even swing the 'Mirrored' private volumes
     over to another CPU if we have a disc crash in the system volume set.
     Our users are then only down for the time it takes to re-boot the
     system (critical systems only). Instead of having to Install from a
     SLT, setup accounting structure, then reload, recover databases, jobs,
     ksam files, etc.

     Since installing Disc Mirroring, System Administration has gotten alot
     less stressful during downtimes. We've got it down to a science, with
     simple directions almost anyone could do the recovery.:) well
     almost...

     If you require 24x7 uptime then, Disc Mirroring should be easy to
     jusitfy.

     Michele




______________________________ Reply Separator ____________________________
_____
Subject: Mirrored Disk/XL
Author:  John Clogg <[log in to unmask]> at CARDINALHEALTH
Date:    2/26/98 6:18 PM




       We use Mirrored Disk/XL and it works great.  If you are
       familiar with
       setting up and using private volume sets, Mirrored disk is
       easy.  Basically,
       you get a different version of VOLUTIL, and you use NEWMIRRSET
       instead of NEWSET and NEWMIRRVOL instead of NEWVOL.  They
       differ
       only in that they allow you to specify two Ldevs for the
       mirrored pair.  It's
       really great when you lose a disc drive and your system doesn't
       miss a
       beat!

       On the other hand, your assertion that it might be overkill is
       certainly valid.
        If, as you say, it's "no big deal" to lose 24 hours' worth of
       work at your
       shop, then I would think it would be hard to justify the cost
       of Mirrored
       Disk/XL and twice as many disks.

       >>> Mark Wilkinson <[log in to unmask]> 02/26/98
       09:57am >>>
       One of our affiliates has just ordered a new 3K and seems to
       have been
       persuaded to get
       Mirrored Disk/XL. I have no personal experience of this and
       none of the
       other 11 Affiliates
       use it.

       Can anyone out there tell me the pros and cons? The system
       tends to be
       supervised by
       a "Super-User" rather than an IS person so we try to keep
       things as
       simple
       as possible
       operationally. To me it sounds like overkill.. The system runs
       maybe 7-8
       users and we have
       Image Logging switched on. We do full backups once in every 24
       hours
       so
       even if the disks
       crash we would lose max 24 hours data which is no big deal.

       Thanks in advance

       Mark Wilkinson.
       Sony Pictures Europe.