A --exclude-checksum option?

[Karl O. Pinc]

Hi,

I use rsync with hardlinks for backup, once a week doing checksums
to ensure there's no filesystem corruption in the
backed-up data.  

I also use tmpwatch, or something similar, to clean up /tmp,
it removes files that have not been accessed recently.
(atime older than some configured limit).
I backup /tmp because I throw stuff in tmp that
I might possibly need again but don't want to bother
having to remember to delete -- and if I'm expecting
to have useful data somewhere I want it backed up.

However, rsync's checksumming (naturally) updates
the atimes of the files in /tmp, and so tmpwatch
never deletes them.

It occurs to me that a handy solution might be
to have an rsync option, similar to
the --exclude option, which would allow checksumming
to happen throughout most of the backup process but
would do "regular" size/timestamp based backups
on certain directories.

What do people think of such an option?
Is there a better design.  (E.g. an option that, er,
preserves atime when checksumming?)
Is rsync just too overloaded with options already
and it would be better instead to run
two instances of rsync?  Is there a bug/feature
in process already that would address the use-case
above?

I'd like to have a sensible design before even
thinking about patching.

Thanks for the feedback.

Regards,

Karl <kop at meme.com>
Free Software:  "You don't pay back, you pay forward."
                 -- Robert A. Heinlein