Integrating Portable and Distributed Storage

We describe a technique called lookaside caching that combines the strengths of distributed file systems and portable storage devices, while negating their weaknesses. In spite of its simplicity, this technique proves to be powerful and versatile. By unifying distributed storage and portable storage into a single abstraction, lookaside caching allows users to treat devices they carry as merely performance and availability assists for distant file servers. Careless use of portable storage has no catastrophic consequences. Experimental results show that significant performance improvements are possible even in the presence of stale data on the portable device.