Sir Isaac Newton's first law--the law of inertia--is as applicable to the world of data management as it is to our planet. Experts estimate that 60% to 80% (or more) of organizational data is never accessed after it's created; files often remain at rest, untouched and unmoved from companies' most expensive storage arrays. Hierarchical storage management (HSM) software can force the migration of these files to more economical resting places while keeping them accessible and retrievable.

HSM software lets users set policies to migrate files from primary disk to other types of storage media based on vendor-provided and user-created policies. These migration policies designate which files to migrate to what storage media, and when these files should be migrated.