By default, rsync decides it can skip transferring the data from a
source file to a destination file if the files have the same size and
last-modified time. Did you preserve last-modified times when you
extracted the files onto the backup machine? If you used tar, the times
should have been preserved by default.

If not, there are two ways you can fix the problem. Extract the archive
again on the server, preserving modification times. Or, if you're
pretty sure that none of the files have changed on the source machine,
run rsync once with the "--size-only" option, which will make it
conclude all the files match and change the times at the destination to
match the source. Future transfers would see the matching times and
skip unchanged files.
--
Matt McCutchen, ``hashproduct''
hashproduct@verizon.net -- http://mysite.verizon.net/hashproduct/

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