Does rsync copy if only perm changed?

[CompuGenic]

Moshe Jacobson wrote:

> On Thu, 9 Jun 2005, CompuGenic wrote:
>
>> I have a 150GB directory tree that I need to rsync nightly. 
>> Periodically I adjust many permissions on this source tree.
>> My question is whether rsync will backup the whole source tree if 
>> only the permissions changed.
>
>
> If you don't specify --whole-file/-W, rsync will do checksums on
> either end to determine if the file is still unchanged, and then it
> will adjust the permissions on the other side.
>
> So no, it will not re-transfer the entire file.
>
> Moshe
>
I'm using hard-links with snapshot backups (as explained in this 
tutorial:  http://www.mikerubel.org/computers/rsync_snapshots/)
to make daily backups. If only the permissions changed on the source, 
will rsync unlink the file before modifying it on the destination? 
Because if so, then it would still be copying the whole file onto the 
filesystem, right?

Here are the details:
I make daily backups in folders called daily.00, daily.01, daily.02, 
etc. Prior to the backup, I shift them all (ie: daily.00 becomes 
daily.01, etc). So daily.00 is always the most recent. However, in order 
to preserve file space, prior to doing the rsync operation, I do "cp -ar 
daily.01 daily.00". Then I do "rsync - ar -e "ssh -i keypath" --delete 
user at remote:/source/path/ /local/path/daily.00/".

Pablo