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Re: Apt and rsync... I know...

Florian Weimer <fw@deneb.enyo.de> writes:

> Florian Weimer wrote:
> > I'm not sure if rsync is the right format for that.  VCDIFF (RFC 3284)
> > should result in smaller deltas and less CPU overhead.  However, I don't
> > know of any free implementation (Subversion has code that does something
> > very similar, though).  The format itself is not encumbered by patents,
> > AFAIK.
> Just for reference, here are a few numbers.  I compared the data.tar
> part of libc6_2.3.2.ds1-10 and libc6_2.3.2.ds1-11 (i386 architecture).
> Delta sizes are:
>   rdiff                        7302952
>   rdiff (gzip -9)              2423336
>   svndelta                     1793107
>   svndelta (gzip -9)           1539271
>   xdelta (-0)                  1751110
>   xdelta (-9)                   935281
> svndelta is quite CPU-intensive, compared to the others.  (I'm not sure
> if it's because of the base64 encoding, which isn't included in the
> numbers above.)  xdelta and rdiff use comparable amounts of CPU time
> (with and without compression). xdelta seems to need memory proportional
> to the size of the input files, which might be a problem.

And what does rsync say? Ucompressed, gzip -9 and gzip with
--rsyncable please.


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