"rsync -z" not working as expected under 2.6.8 and 2.6.9?

Jason Haar Jason.Haar at trimble.co.nz
Fri Oct 13 00:08:54 GMT 2006

I got curious as to how rsync operates, and got a few tests going under
ethereal. The results confused me more.

I created /tmp/test-out/ containing two different text files - one named
"file.txt" and the other "data.gz". ie. data.gz wasn't actually
compressed - it was actually text. I then created an empty directory on
a rsync server to replicate that data to.

I did a "rsync -av /tmp/test-out/ rsync://server/share/test-in" with
ethereal running. As expected, ethereal shows the uncompressed contents
of both files being sent.

Then I reset and did a "rsync -azv /tmp/test-out/
rsync://server/share/test-in" with ethereal running. Unexpectedly there
was no sign of uncompressed data in the packet trace! Looks like rsync
"decided" to compress data.gz even though /etc/rsyncd.conf had "*.gz" in
it's "dont compress" section... Looking at the packets, I see no
evidence of the rsyncd server telling the client anything regarding the

So is there some smoke-n-mirrors going on in there? Why did the client
compress data.gz - even though it was mentioned on the server as "dont

Enquiring minds would like to know :-)



Jason Haar
Information Security Manager, Trimble Navigation Ltd.
Phone: +64 3 9635 377 Fax: +64 3 9635 417
PGP Fingerprint: 7A2E 0407 C9A6 CAF6 2B9F 8422 C063 5EBB FE1D 66D1

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