Changing dpkg-deb default compression from gzip to lzma for Hardy

Krzysztof Lichota krzysiek at
Mon Dec 17 12:05:26 UTC 2007

Scott Ritchie napisaƂ(a):
> I did some experimentation with my Wine package.  Here's the filesize of
> the latest .deb passing different options to dpkg-deb:
> 11081456 default
> 10090930 bzip2
> 7682608 lzma
> That's over a 30% reduction in bandwidth for me and my humble third
> party repository.
> I've heard that lzma will be included by default in main for Hardy.
> This is a very good idea.  Changing package build scripts to manually
> pass lzma compression using dh_builddeb -- -Z lzma would be very
> tedious, however.  In IRC pitti proposed that we do this centrally -
> changing the default of dpkg-deb (currently gzip) seems to be the best
> place for this.
> Thoughts?

It is hard to judge best compression using only one package. It is
possible that for other packages other compression schemes would be
better. Have you run built other packages? ?The best would be to rebuild
whole repo with new compression scheme and compare the results, so that
it does not appear, for example, that packages stop fitting into one CD.

Another thing is decompression time - on some machines the limiting
resource is CPU, not bandwidth nor disk space and changing compression
would mean significant burden as packages would be unpacked much longer
and put more stress on system, making user experience unpleasant. This
could be mitigated by running unpacking process with "nice", but AFAIK
it is not the case now.

If these 2 issues are addressed, I think it in general a good idea :)

My 2c.

	Krzysztof Lichota

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