We have a web app on a number of servers and we want to add an additional layer of redundancy by backing up the key data to S3. The key data is the MySQL database and a folder containing dynamically created site assets - predominantly images. Some kind of rsync based solution would initially seem the best plan. A couple of years ago we played with S3cmd (in particular s3cmd sync) with some success but we didn't find it particularly reliable although this may have changed since. Its occurred to me though that a rsync solution might not work particularly well with a single db.sql file created with mysqldump and I assume this means the whole database getting transferred each time, with multiple databases of over 1GB this is going to add up to a lot of traffic (and $s) very quickly. With the image files I could simply just transfer files modified within the last day which would be far more simple. What approach should I look at?