Using zsync for .deb downloads: initial benchmark results

[Lars Wirzenius]

pe, 2009-07-17 kello 12:20 +0100, Matt Zimmerman kirjoitti:
> On Tue, Jul 14, 2009 at 07:19:31PM +0300, Lars Wirzenius wrote:
> > * rsyncable: This makes it easier for zsync to do magic things with gzip,
> >   by recompressing the gzipped tarballs within the .deb files with gzip
> >   --rsyncable. This provies a lot of improvement. Saving a quarter of
> >   the bandwidth is already fairly significant, especially since the
> >   size impact on the .debs is less than 1%. 
...
> > * rsyncable3: Some packages use lzma or bzip2 compression of the
> >   tarballs within the .deb. This benchmark converts those to be
> >   compressed with gzip --rsyncable. This improves things a bit compared
> >   to just rsyncable, at a 17% increase in size compared to rsyncable.
> >   Because most of the packages using lzma are OpenOffice.org related,
> >   it is probably not realistic to make them use gzip --rsyncable due
> >   to CD size limits, but it might be possible to use them for updates
> >   that don't get put into CDs.
> 
> Do you have figures for how much the size of the .debs increased in each of
> these scenarios?  We obviously need to take this into account as a cost of
> the change, particularly considering the limitations on the size of the
> ISOs.

rsyncable: just under 1%. rsyncable3: about 18%.

Thus, using --rsyncable should be doable for the CD, but re-compressing
things with gzip instead of lzma or bzip2 is not.