What is data de-duplication? In simplified terms, data de-duplication means comparing objects (usually, files or blocks) and removing all non-unique or duplicate objects (copies). It's a hot technology in storage because it enables companies to save a considerable amount of money and is quite versatile, giving companies three main options to implement it: Host based, appliance based, and storage based.

In chapter 13 of "Storage Area Networks For Dummies," important concepts of data de-duplication are detailed. The techniques described are designed to "lighten the load" of a company's data storage infrastructure, freeing up crucial storage space, and eliminating multiple instances of the same data.