Subject: Re: dump to tape
To: Julian Coleman <jdc@coris.demon.co.uk>
From: Claude Marinier <claude.marinier@dreo.dnd.ca>
List: netbsd-help
Date: 04/20/2001 10:25:15
Julian,

Yes, I tried different tapes and I cleaned the unit very recently.

It is looking more like a hardware issue.

Thanks.

P.S. What about the -B option? Is it better to use it rather than the
     density and length options?

On Fri, 20 Apr 2001, Julian Coleman wrote:
> > This was working until recently. There are two possibilities here.
> >
> > 1) The system may have developed a hardware problem.
> >
> > 2) The dump script is flawed and the flaw is causing a problem now
> >    because the partitions have exceeded the size I specify with the
> >    dump parameters.
>
> Don't think it's 2), see below ...
>
> > b=126
> > d=108000	# original Exabyte uses 54000, Eliant is double that
> > s=8500		# for 160m tape (note that 160*6000/112=8571)
> > 		# standard 112m uses 6000
> > f=/dev/nrst0
> > dump 0ubdsf $b $d $s $f /
>
> I've been using "-d 54000 -s 6000 -b 56" on an 8500 and now an 8505 without
> problems.  I recall reading somewhere that 56 was the optimum block size for
> Exabyte.  Not sure if it applies to newer drives.  Of course, once you have
> done one dump, the amount of tape left will be less than these figures, but
> that should be fine - all I think you really need to do is to stop dump from
> thinking the tape is shorter than it is.
>
> > > dump 0ubdsf 126 108000 8500 /dev/nrst0 /
>
> > >   DUMP: estimated 62012 tape blocks on 0.01 tape(s).
>
> > >   DUMP: DUMP IS DONE
> > > dump 0ubdsf 126 108000 8500 /dev/nrst0 /usr
>
> > >   DUMP: estimated 1224630 tape blocks on 0.18 tape(s).
>
> > >   DUMP: End of tape detected
>
> The first dump is fine and uses a small fraction of the tape.  The second
> dump estimate is for less than one tape.  However, dump gets an EOM from
> the drive, so it prompts for a new tape.
>
> When I had problems with my 8500, the tape would just stop, but I don't know
> how the Eliant would behave.  I take it you've tried different tapes and also
> cleaning the heads?

-- 
Claude Marinier, Information Technology Group    claude.marinier@dreo.dnd.ca
Defence Research Establishment Ottawa (DREO)    (613) 998-4901  FAX 998-2675
3701 Carling Avenue, Ottawa, Ontario  K1A 0Z4         http://www.dreo.dnd.ca