Defensive Design: Developing a System-Agnostic Repository for Sustainable Long-Term Preservation

Colenda, the University of Pennsylvania Libraries’ digital repository, was designed to promote longterm preservation. Its infrastructure is comprised of components selected to concentrate on factors that are of the most importance and that pose the greatest risks for long-term preservation of digital assets: safe file storage, the ability to track changes to objects over time, mechanisms for object management and discoverability, and migration paths that guarantee that objects can be safely migrated to new software and new versions of existing systems while preventing data loss. Favoring a pluggable architecture and preservation of software-agnostic representations of objects in order to keep future repository development plans flexible and open, our approach minimizes the risk of data loss in the long term and has allowed us to design a system in which the right tools for the task are always an option. In this paper, we will enumerate the risks/concerns influencing our design decisions and show how our approach addresses them while retaining a connection to the central open-source projects of the community, Fedora and Samvera, that make up significant portions of our stack.