but why shut down the network? it can be very handy to have it running if /
when you really do have a tape or tapedrive problem; beats driving to work
at 2am.
> -----Original Message-----
> From: John Clogg [mailto:[log in to unmask]]
> Sent: Wednesday, March 23, 2005 10:44 AM
> To: [log in to unmask]
> Subject: Re: Hung tape enhancement request
>
>
> We had a similar problem with DLT drives. In our case it was
> not caused
> by the drive itself, so I don't think the type of medium
> matters. This
> may or may not relate to your situation, but here is what was
> happening:
>
> As a prelude to performing the synchronization point of our online
> backup each night, we shut down all jobs and sessions (except
> the backup
> job) and shut down networking (NETCONTROL STOP). We learned that any
> time you stop and restart networking, it is necessary to
> restart the STM
> monitor processes used by the CSTM diagnostics, so we run STMSHUT.DIAG
> before shutting down the network, and run STMSTART.DIAG after
> restarting
> it. This was the source of the problem. When the diagnostic
> monitor is
> started by STMSTART (or when the system is started), it goes through a
> hardware mapping process. That process runs diagnostics on
> peripherals
> as it encounters them. If you mount a tape while that is
> happening, the
> diagnostic process and the AVR (automatic volume recognition) process
> get into some kind of deadlock, and a reboot of the system is the only
> way to get the drive back.
>
> The solution for us was to forbid any tape mounts or other use of the
> tape drives for several minutes after restarting the
> diagnostic monitor.
> It's kind of like not swimming after eating.
>
> I hope this is helpful to someone!
>
> John
> -----Original Message-----
> From: HP-3000 Systems Discussion [mailto:[log in to unmask]] On
> Behalf Of Dave Powell, MMfab
> Sent: Tuesday, March 22, 2005 3:25 PM
> To: [log in to unmask]
> Subject: Hung tape enhancement request
>
> If it's not too late to make requests... How about fixing whatever
> causes
> our tape drive to hang about 2 or 3 times a year. HP seems
> to think it
> is
> tied in with the ghost-session problem that others have mentioned..
> Might be,
> but we never have anything hang except the tape drive.
>
> Details from last night's hang:
> A500, MPE 7.5 pp2 (just updated Saturday), DDS-3, an old tape (used
> about 20
> times with no prior problems)
> Drive now shows as 'UNAVAIL', owned by 'SYS'.
> Backup ran normally. Finished 11:05 pm.
> Drive failed to come back on line. Backup job noticed the drive was
> "UNAVAIL", waited about 10 times longer than it usually takes, then
> started
> the verify anyway, at 11:16 pm.
> Verify said "DEVICE UNAVAILABLE (FSERR 55)" and " VSTORE ENCOUNTERED
> FOPEN
> FAILURE ON DEVICE FILE "T" (S/R 2213)". Then it just sat there.
> At 2:51 a watchdog job concluded that the backup job was hung, did a
> showdev 7
> (it was 'UNAVAIL', owned by 'SYS', issued a few abortios on it (but
> never got
> the "no io to abort" message), then abortjobed it. Job
> aborted ok first
> time.
>
> This morning I fed it ever-increasing abortio while-loops, and finally
> got the
> 'no io to abort' message after about 2,600 total abortios. But that
> does not
> mean that there were 2600 ios to abort. If I do a single
> abortio at the
> console, I still don't get the 'no io to abort' message.
> Further while
> loops
> in jobs with no pauses seem get the warning after between 50 & several
> hundred
> repetitions. 2600 just happens to be how many total tests it took for
> me to
> get impatient enough to feed it a big enough while-loop with
> no pauses.
> Tape
> drive is STILL 'UNAVAIL', owned by 'SYS'.
>
> Dave ("planning to reboot tonight") Powell, MMfab
>
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