Challenge: dump | restore

Bodo Thiesen bothie at
Sat Nov 13 15:40:19 UTC 2010

* Edward Ned Harvey <kernel at> hat geschrieben:
> dump -0af - /dev/someVG/sourceFS | restore -rf -
> My only guess is that there seems to be something wrong with the pipe.
> Like, it's not streaming the bits properly or something.  Is it possible to
> overflow a pipe or something?

The sending process should block until the receiving process reads the

> I can't think of any good explanation for
> this weird behavior.  What could cause a pipe to break, aside from the
> receiving process terminating unexpectedly?

I recommend using strace to trace it down:

strace -f -o dump.strace dump -0af - /dev/someVG/sourceFS | \
strace -f -o restore.strace restore -rf -

Then take a closer look on the tails of the two files, maybe that reveals
the problem already.

Regards, Bodo

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