Safety in Numbers: Distributed Digital Preservation Networks
It has long been recognized that there is safety in numbers and that redundancy enhances survivability. This principle has been applied in many spheres of human activity, from engineering to military science. It is now being applied in librarianship and digital preservation, through the creation of distributed digital preservation (DDP) networks using the open-source LOCKSS (“Lots of Copies Keep Stuff Safe”) software. This paper describes two Private LOCKSS Networks (PLNs) based in North America: the MetaArchive Cooperative, an international preservation network serving more than 50 member institutions in the U.S., Brazil, Spain, and the U.K.; and the Alabama Digital Preservation Network (ADPNet), a state-based preservation network serving academic libraries, public libraries, and the state archives in Alabama. The paper argues that PLNs offer a technologically robust, administratively manageable, and economically sustainable way to protect digital assets and ensure the continuity of digital libraries in the face of natural and man-made disasters.