Binary diffs for deb files

dave kempe dave at solutionsfirst.com.au
Tue May 2 13:30:34 BST 2006


James Hall wrote:
> The deb file needs to be decompressed then put together again since
> doing binary diffs on gzip'ed files make very large diffs. Usually as
> large as the file itself - making the diff completely pointless. Zsync
> on compressed deb's would save no bandwidth.

what about if you used the --rsyncable switch to gzip?
from man gzip:
--rsyncable
               While compressing, synchronize the output occasionally 
based  on the  input.   This  increases  size  by less than 1 percent 
most cases, but means that the rsync(1) program can much  more 
efficiently syncronize files compressed with this flag.  gunzip
cannot tell the difference between a compressed file  created  with this 
option, and one created without it.

I have used it with mysql dumps and rdiff-backup very effectively

dave



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