On Fri, Dec 31, 2004 at 03:02:15PM +0100, Peter Guhl wrote:
> Hello all
> 
> This error happens all the time - but sometimes it vanishes and then it
> comes again. Now I have got the idea that the space allocated at the
> holding disk is too small (not the holding disk itself). The only other
> explanation is a hardware defect on the DLT Drive but mt and every other
> diagnosis I tried don't look like that.
> 
> Could it be that I am on the right track?
> 
> Is it a general problem that there's less space at the holding disk than
> at the tape? I guess not because in the past this was fairly common.

A grep for "short write" in the source files shows it present
in only two files, taper.c and tapeio.c.  This confirms my
notion on reading your note that it is a tape problem, not
a holding disk problem.

I only see that particular message when the total size of what is being
taped (all DLE's total size) is greater than the capacity of a single
tape.  The last DLE that tried to fit on the tape does not, so it gets
a "short write".  In my case, with multiple tapes per dump, the DLE
that encountered the end of the tape gets put first onto the next tape.

Depending on your setup the same could happen or the DLE could be left
on the holding disk for later flushing (automatic or manual) or the
dump could fail if it were being written direct to tape.  This latter
situation is the only one I can think of where the holding disk would
come into play.  But it would have affected whether the dump went to
tape or holding disk, not whether it got the short write.

Have you modified the "reserve" parameter from the default 100%.  That
does affect how much of your holding disk is available for level 0 dumps.

jl
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Jon H. LaBadie                  jon AT jgcomp DOT com
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