full upload happening even though only a timestamp has changed

Tom Goulet tomg at em.ca
Tue Apr 22 12:43:13 EST 2003

> The second time the file had a different timestamp, so it "rsync'ed" it.
> This means it rebuilt the file using the existing file as a basis, using
> the rsync algorithm to try and find "matching" blocks in the existing
> file. The fact that they all matched means it didn't need to transfer
> any data, but it still needed to negotiate with upstream to determine
> that they "matched".

I understand all that theory now pretty well :-).  But it *did* transfer
all the file data.

> The checksum bit as you describe it only occurs with the '-c' option.
> Without this option rsync generates a "signature" that is transmitted
> upstream and used to generate a "delta" that is applied to the "basis"
> to update the file. If the files turn out to be identical the delta
> turns out to be very small (ie, "nothing changed"), but it is still
> applied to update the file.

Okay, thank you.  I was assuming a checksum was the same as the
signature you describe.

> However, from the "wrote 731164664 bytes" it looks like you might have
> hit the known problem jw mentioned. The workaround for this is to use a
> sufficiently large block size. Try using -B 65536.

I've used that command line option and shown the output in my previous
mail.  JW seems to be convinced now.  Now I'm starting to feel less like
the guy who saw a dragon only to have all his friends say "Are you sure
it wasn't a crocodile?".

> BTW, how fast is the connection? 700M in 11 minutes is pretty fast. 10M
> ethernet?

Yeah.  But I went and reported this problem because with this problem
and the --partial command line option I clobbered a 700MiB file on the
other end of a 12KiB/s upload link.

Tom Goulet, tomg at em.ca, D8BAD3BC, http://web.em.ca/~tomg/contact.html
I usually read no mail which is unsolicited and bulk, is not exclusively in
plain text, has advertising footers, is top-posted, or has bad line wrap.
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