--ignore-existing

[mumbly]

I'm doing a backup of a directory where no files ever get updated, only new files created, so it would be nice to have s3sync work more efficiently by only worrying about files that don't exist on the receiving side. --size-only would help, but is still not as efficient.

Thanks. Great product.

--Tim

[ferrix]

You could use 'find' to get only new files, and pipe that to s3cmd.  Not a one-click type solution, but if you're concerned about efficiency maybe that's ok.