[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

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

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,

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.

Current mail filters: many dial-up/DSL/cable modem hosts, and the
following domains: atlas.cz, bigpond.com, freenet.de, hotmail.com,
libero.it, netscape.net, postino.it, tiscali.co.uk, tiscali.cz,
tiscali.it, voila.fr, wanadoo.fr, yahoo.com.

Reply to: