rsync dir in _both_ directions?

Dave Dykstra dwd at
Thu Feb 7 07:49:35 EST 2002

On Wed, Feb 06, 2002 at 02:14:23PM -0600, Jack McKinney wrote:
>     If I add 512 bytes at the begining of the file, then I would expect
> it.  If I only add 14 bytes, then I don't think rsync will detect this,
> as it would require it to compute checksums start at EVERY byte instead
> of 512 byte checksums at offsets 0, 512, 1024, 1536, et al.
>     It is an easy experiment.  Create a large text file (e.g., uuencode
> a decently large binary) and rsync it to another machine and time it.
> Then, edit it, and change ONE BYTE and rsync again.  It should go much
> faster because only one block has changed.  Then, edit it a second time
> and add a new line at the top that says Kilroy was here.  This will add
> 17 bytes to the file (13 letters, two spaces, one period, one newline).
> Then rsync it again.  I suspect that your xfer time will be comparable to
> the first one, not to the second.

I did try it.  Did you?  It works.  Look at the "speedup" printed by -v
and the total bytes transferred.

- Dave

More information about the rsync mailing list