Design And Implementation Of A Distributed Network Mutex

With the rapid development of the computer network, distributed applicationsbecome main stream gradually. Because of its inherent shortcomings, traditionalcentralized server system limits the development of network service to multi-aspectmore and more, people also turn to use distributed server system slowly. Usingdistributed system has many advantages, such as sharing resource,improving systemreliability and reducing business cost. In order to meet the need of distributed andparallel server system, which has high performance, high scalability and with areasonable price, we have developed a distributed and parallel file system based onLinux kernel, named DPFS. DPFS is server-oriented, on which we can build adistributed and parallel server system, BOD server system is just a typical example.In the thesis, we firstly discuss some important issues in design of distributed filesystem and then introduce the collectivity structure and all modules'function ofDPFS. Lastly as emphases, we describe the design and realization of network mutualexclusion lock based on PQ-RW mutual exclusion algorithm, including the read-writecoherence issue of DPFS, the analyzing and comparing of some typical mutualexclusion algorithms, the describing and realization of PQ-RW algorithm, therealization of network mutual exclusion lock and the testing and analyzing of theperformance.The PQ-RW algorithm is a distributed mutual exclusion algorithm based on thepriority queue and hoeld the read-write character. The network mutual exclusion lockbased on it is the fundamental guarantee which the DPFS used it to implement mutualexclusion accessing to the critical resource of each server site, and to resolve thecoherence issue of read-write. By using the algorithm, some systems, in which mostdata access is read-only, can greatly reduce latency of concurrent control and amountof message. At the same time, through added an invalidation checking mechanism ofsites and locked process, it most improved the performance of the network mutualexclusion lock.