A flexible algorithm for replicated directory management

A replicated directory management algorithm is presented that supports full location-transparency by allowing migration and reconfiguration at the granularity of individual names. Initially, all names in a directory (including names not yet in use) are controlled by the same set of sites, but control over any individual name (or range of names) can be migrated, e.g. to the set of sites that control the data object associated with the name. The method is based on a directory replication algorithm of J.J. Bloch et al. (1987), incorporating two extensions: (1) allowing control over individual names in a directory to migrate independently; and (2) allowing the definition of relationships among names, such that if control over a given name migrates, then those names that depend on it are automatically migrated as well. Finally, it is stated that the major cost of the algorithm, compared to simpler approaches that do not provide the same degree of location transparency, is the additional complexity and difficulty of obtaining a consistent view of the entire directory.<>