It has long been recognized that there is safety in numbers and that redundancy enhancessurvivability. This principle has been applied in many spheres of human activity, fromengineering 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-sourceLOCKSS (“Lots of Copies Keep Stuff Safe”) software. This paper describes two PrivateLOCKSS Networks (PLNs) based in North America: the MetaArchive Cooperative, aninternational 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-basedpreservation network serving academic libraries, public libraries, and the state archives inAlabama. The paper argues that PLNs offer a technologically robust, administrativelymanageable, and economically sustainable way to protect digital assets and ensure thecontinuity of digital libraries in the face of natural and man-made disasters
