Exploiting weak connectivity in a distributed file system
Lily Mummert, Mahadev Satyanarayanan · 1996
Weak connectivity, in the form of intermittent, low-bandwidth, or expensive networks is a fact of life in mobile computing. For the foreseeable future, access to cheap, high-performance, reliable networks, or strong connectivity will be limited to a few oases, such as work or home, in a vast desert of weak connectivity. The design of distributed file systems has traditionally been based on an assumption of strong connectivity. Yet, to provide ubiquitous data access, it is vital that distributed file systems make effective use of weak connectivity. This dissertation describes the design, implementation, and evaluation of weakly connected operation in the Coda File System. The starting point of this work is disconnected operation, in which a file system client operates using data in its cache during server or network failures. Disconnected clients suffer frommany limitations: updates are not visible to other clients, cache misses may impede progress, updates are at risk from client loss...