AGGREGATED OPPORTUNISTIC LOCK AND AGGREGATED IMPLICIT LOCK MANAGEMENT FOR LOCKING AGGREGATED FILES IN A SWITCHED FILE SYSTEM

摘要

A switched file system, also termed a file switch, is logically positioned between client computers and file servers in a computer network. The file switch distributes user files among multiple file servers using aggregated file, transaction and directory mechanisms. The file switch supports caching of a particular aggregated data file either locally in a client computer or in the file switch in accordance with the exclusivity level of an opportunistic lock granted to the entity that requested caching. The opportunistic lock can be obtained either on the individual data files stored in the file servers or on the metadata files that contain the location of each individual data files in the file servers. The opportunistic lock can be broken if another client tries to access the aggregated data file. Opportunistic locks allows client-side caching while preserving data integrity and consistency, hence the performance of the switched file system is increased.