Six easy ways to speed up backups
The next step is to decide what you want to do with different types of files and the then set criteria such as length of retention for the different categories. It may turn out that all those JPEGs cluttering up everyone's disks aren't just collections of naughty pictures, for instance, and simply banning JPEGs from backups will create more problems than it solves. It might better to use a single-instance storage scheme for all those charts saved in JPEG format rather than trying to eliminate JPEGs altogether."