Guaranteeing consistency between large replicated writable disk images

We describe a distributed protocol that guarantees the consistency of multiple replicas of a given disk image represented by a large file. The image replicas are used as read/write caches for the primary disk image located at a server. The protocol allows stale caches to be incrementally invalidated minimizing the amount of data that must be copied and recopied from the server. We prove that the protocol ensures the consistency of the disk from the point of view of any client using it, and we describe an implementation within an existing streaming framework.