FICUS: a very large scale reliable distributed file system
II Richard George Guy · 1992
The dissertation presents the issues addressed in the design of Ficus, a large scale wide area distributed file system currently operational on a modest scale at UCLA. Key aspects of providing such a service include toleration of partial operation in virtually all areas; support for large scale, optimistic data replication; and a flexible, extensible modular design. Ficus incorporates a stackable modular architecture and full support for optimistic replication. Replication is provided by a pair of layers operating in concert above a traditional filing service. A abstraction and on-the-fly volume grafting mechanism are used to manage the large scale file name space. The replication service uses a family of novel algorithms to manage the propagation of changes to the filing environment. These algorithms are fully distributed, tolerate partial operation (including nontransitive communications), and display linear storage overhead and worst case quadratic message complexity.