Greetings from a cold winter's day down under:
 
Mirroring disks on the HP3000 doesn't seem to be as popular
as it is on the HP-UX platform.  I wonder why?
 
Over the past 15 years or so, we have suffered three disk
failures without mirroring.  Each time was a nightmare,
involving 24 or 36-hour marathons of solid repair/re-load/re-build/
whatever was necessary.  Despite good backups, there was
always substantial data loss, and a lot of 'hidden cost' in
re-entry.
 
Last Wednesday, round about 5:30 a.m., we suffered our
fourth disk failure.  With MirrorDisk/iX, the system stayed
up--users didn't even know it happened.  It was the third
(last) spindle on a private volume.  We took the system
down at 12 noon, ran some diagnostics that proved the
disk was dead enough to replace, swapped in a new mechanism,
brought up the system, did a suspendmirrvol, replacemirrvol,
then sat back and watched the spindle repair itself, and
then let the users back on.  1 hour and 15 minutes total
down time, and NO DATA LOSS.
 
Of course that down time could have been reduced if I had
forgone diagnostics, and let users back on as soon as the
system was up, but I wanted to see the volume back up perfectly
intact.  And 75 minutes is insignificant compared to what
we've suffered without mirroring.
 
Guess where the bulk of my votes went on the recent systems
improvement committee ballot?
 
Cheers,
Ron Burnett
Royal Children's Hospital
Melbourne, Australia
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