(Fwd) Re: SCSI tape data loss

[Kern Sibbald]

Hello Dan,

On Wed, 2003-08-27 at 20:15, Dan Langille wrote:
> On 27 Aug 2003 at 11:06, Nate Lawson wrote:
> 
> > On Wed, 27 Aug 2003, Kern Sibbald wrote:
> > > Many thanks for testing this ...
> > >
> > > It seems to me that your tests, clearly indicate that
> > > there is a problem even though you had no data loss.
> > >
> > > When you ran without -pthread, the status
> > > received by the program was a 0 with 141776
> > > blocks written. This is correct.
> > >
> > > When you ran with -pthread, the status
> > > received by the program was a -1 with 142879
> > > blocks written. This is "not correct".
> > >
> > > To me, that shows very clearly that with -pthread
> > > the 0 status was lost and more blocks were written.
> > > In fact, in this case so many blocks were written
> > > that the tape was not properly terminated with
> > > an EOF (actually two EOF marks).
> > 
> > Here is a response I got by forwarding this to the pthreads maintainer:
> > > A return status of 0 from write is not interpreted as an End-Of-Tape.
> > > The threads library isn't smart enough to know that the file
> > > is a tape device and that a 0 status should break it out of the
> > > loop.  Thus, it continues writing.
> > >
> > > Use libkse :-)
> > >
> > > --
> > > Dan Eischen
> 
> Nate: thanks for getting in touch with him.
> 
> It is interesting to note that the code works OK on Linux and 
> Solaris.  Why is FreeBSD different in this case?
> 
> Kern: I can't comment on libkse.  I don't know it and I don't know 
> what effect it would have on Bacula.

I cannot comment on libkse either since I don't know what
it is, and it is not indexed in the FreeBSD man pages --
at least not under libkse.  

Best regards,

Kern
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