[Info-vax] Unpleasant Disk Shadowing Surprise

[tadamsmar]

On Oct 11, 11:18 am, abrsvc <dansabrservi... at yahoo.com> wrote:
> On Oct 11, 10:53 am, tadamsmar <tadams... at yahoo.com> wrote:
>
>
>
>
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> > This is VMS 7.3-2 on a DS10.  I am at V19.0 on patch updates (applied
> > in July 2009)
>
> > Our real-time application halted for more than 3 minutes.
>
> > After the incident I found here was a disk error on one member of the
> > shadow set.
>
> > The first indication was whe the application watchdog alarm went off.
>
> > According to the console log, more than 30 seconds after the watchdog
> > sounded, the shadow set changed state, the offending disk went
> > offline, a mount verification started and completed.
>
> > Immediately after the mount verification completed, VMS started
> > working again.
>
> > Looks like the disk system was inaccessible for about 3 minutes and
> > any process that tried to use it got
> > halted somehow.
>
> > Is this to be expected?  We have had VMS and disk shadowing running
> > the application for 20 years or so, but I don't know that we have ever
> > had a disk error while the watchdog was configured to sound, so we
> > might not have noticed the halting and recovery.
>
> Something sounds a bit fishy here.  Unless the entire shadowset went
> offline, there should not have been any interruption.  You may see a
> slight performance hit with one member rather than 2, but even that
> should be minimal.  Something else was happening here.  Can you
> determine whether or not the entire shadowset went offline?
>
> Dan- Hide quoted text -
>
> - Show quoted text -

I have not dug into the error log yet.

The console log shows only one disk going off line.

I guess I need to analyze the error log.