full upload happening even though only a timestamp has changed

jw schultz jw at pegasys.ws
Tue Apr 22 10:23:03 EST 2003

On Tue, Apr 22, 2003 at 12:11:10AM +0000, Tom Goulet wrote:
> Hello,
> For no apparent reason Rsync is uploading the whole file even though the
> the remote file is identical to the local file.  Here is a transcript to
> demonstrate what is going wrong:
> tomg at nova:~/mylibrary$ rsync -rtlPvessh /extra/library teep:/extra/tomg
> building file list ...
> 46349 files to consider
> wrote 1358812 bytes  read 20 bytes  44551.87 bytes/sec
> total size is 5240249974  speedup is 3856.44
> tomg at nova:~/mylibrary$ touch /extra/library/software/Knopper,_Klaus/KNOPPIX_V3.2-2003-04-18-EN.iso
> tomg at nova:~/mylibrary$ rsync -rtlPvessh /extra/library teep:/extra/tomg
> building file list ...
> 46349 files to consider
> library/software/Knopper,_Klaus/KNOPPIX_V3.2-2003-04-18-EN.iso
>     12288000   1%    1.05MB/s    0:11:09
> It will take eleven minutes or so and upload the entire thing.  What I
> expected to happen was Rsync doing its checksum thing on the entire file
> and then not uploading anything because the file was the same.
> Here are listings of two files on the remote host to show that uploading
> is really happening:
> -rw-------    1 tomg     users    104792064 Apr 21 18:07 .KNOPPIX_V3.2-2003-04-18-EN.iso.vNUGjU
> -rw-r--r--    1 tomg     users    729716736 Apr 21 13:55 KNOPPIX_V3.2-2003-04-18-EN.iso
> Local Rsync is version 2.5.6-0.1 on Debian testing.  Remote Rsync is
> version 2.5.4 on Slackware 8.0.  If I recall correctly, the same problem
> happened with a remote Rsync of version 2.5.5-0.1 on Debian testing.
> Is this a bug?  Am I doing something wrong?  Please give me a CC as I am
> not subscribed.

If the mtime indicates the file has changed it will do an
update.  That doesn't mean that any actual file data will be
transfered.  If all the blocksums match it will effectively
do a local copy to the temp file and then rename back.  If
you want it to do a whole-file checksum as part of decideing
whether to update you will need to use the -c option which
overrides mtime.

	J.W. Schultz            Pegasystems Technologies
	email address:		jw at pegasys.ws

		Remember Cernan and Schmitt

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