Data Deduplication, or "dedupe", essentially refers to the elimination of redundant data. In the deduplication process, duplicate data is deleted, leaving only one copy of the data to be stored. However, indexing of all data is still retained should that data ever be required. Deduplication is able to reduce the required storage capacity since only the unique data is stored, and compares segments of data being written to disk storage with previously stored data segments. All unnecessary duplicate files are removed. Deduplication is a data reduction technique that makes storage more efficient and dramatically reduces expenses for the entire IT infrastructure.