[Info-vax] Unpleasant Disk Shadowing Surprise

[tadamsmar]

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.