On Fri, Nov 24, 2000 at 11:14:49AM -0500, Lillian Kulhanek wrote:
> Hey gang,
> Quick question that I haven't been able to find in the docs. (If the
> answer's there, apologies for not RTFM more thoroughly, please point me to
> the URL). When rsync first gets to a file, does it first compare timestamps
> to determine if it needs to run the delta checksums, or does it run the
> delta checksums straight off?
By default it first compares timestamps but there are many options to
control the algorithm it uses.
> I ask because, this handy utility rsync has allowed me to see how many of
> the ten's of thousands of files on our servers are actually modified
> throughout the day - relatively very little. (Neat side effect: It's
> allowed me to create a usage benchmark.) In our case, I think it's
> inefficient for rsync to run checksums on every single file, if that is
> indeed what it is doing. If this is the case, is there a way I could force
> it to first look for changes in timestamps (which would be quicker), and
> then do its thing only when it sees file timestamp differences?
> (Hmm, there is the issue of restoring a file from tape with an older
> timestamp.)
It looks for exact matches in timestamps so don't worry about backups.
Since you don't appear to be getting the default behavior perhaps it would
helpful for you to post more details, of the operating system(s) and
rsync options you're using.
- Dave Dykstra
