File Fixity in the Cloud: Policy, Business, and Technical Considerations

When shifting storage managed on-premises into the cloud, many digital preservation repository managers must reevaluate their approach to guaranteeing file integrity. Most cloud storage vendors offer guarantees of file durability that call into question the need for continuous fixity checking. At the same time, cloud vendors tend to charge fees for bringing computational resources to bear on individual files, turning continuous fixity checking into a potentially burdensome expense. With these technical and business considerations in mind, this paper explores one institution’s solution to verifying fixity in a repository of approximately seventeen million files after shifting on-site storage into the cloud. It evaluates broader considerations for the field of digital preservation when considering file integrity in the cloud and concludes with an explanation of a local policy for affordable ongoing fixity monitoring adapted to the affordances of a cloud-adapted architecture.