can rsync scan files only with mtime since T?

[Jamie Lokier]

Matt McCutchen wrote:
> > Is this doable with current rsync?
> 
> No.  A request for enhancement has been entered for a --newer option
> that would do this: https://bugzilla.samba.org/show_bug.cgi?id=2423 .
> At present, I can think of two things you might try:
> 
> 1. Use `find' to list the files that need to be checked and pass the
> list to rsync using --files-from, as described in the request for
> enhancement.
> 
> 2. Use Unison ( http://www.cis.upenn.edu/~bcpierce/unison/ ) instead
> of rsync.  If I understand correctly, since Unison stores the state at
> the last synchronization on both sides, the local Unison knows which
> files have changed since then and mentions only those files to the
> other side.  (Someone please correct me if I am wrong about this.)

A really nice solution would be for rsync to use the rsync delta
transmission algorithm (or something like it) to compare the set of
file attributes between each end.

I've always found it peculiar that rsync transmits the full list of
files, as that can be quite slow in some scenarios.

For backups that would be better than a --mtime option, as mtimes
cannot always be assumed to increase.  In general, it would have the
potential to speed up transfers involving large numbers of files when
little data changed.

-- Jamie