分布式网络互斥锁的设计与实现

【作者】 庞飞；

【导师】 杨国纬；

【作者基本信息】 电子科技大学 ， 计算机系统结构， 2005， 硕士

【摘要】 随着计算机网络的快速发展,分布式应用逐渐成为主流。传统的集中式服务器系统因其固有的,诸如单一故障点、可扩展性差等缺点,越来越制约着网络业务向多元化方向发展,人们也慢慢地转向使用分布式服务器系统。使用分布式系统的好处很多,例如可以实现资源共享、提高系统可靠性、降低商业成本等等。为了满足众多信息服务提供商对高性能、高性价比、高可扩展性的分布式并行服务器系统的需求,我们基于Linux 内核开发了具有自主知识产权的分布式并行文件系统DPFS。DPFS 是一种面向服务器的分布式并行文件系统,在其基础上可以构建分布式并行服务器系统,典型应用就是宽带视频点播(BOD)服务器系统。本文首先讨论了在分布式文件系统设计时面临的几个重要问题,然后给出了DPFS 的总体结构,并介绍了各模块的功能特点。最后重点描述了基于PQ-RW算法的网络互斥锁的设计与实现,包括下面主要内容:DPFS 读写一致性问题、几种典型的互斥算法的分析比较、PQ-RW 算法的描述和实现、网路互斥锁的实现、性能测试和分析。PQ-RW 算法是一种基于优先权队列的具有读写特性的分布式互斥算法。基于该算法实现的网络互斥锁,是DPFS 用来对各个服务器节点中的临界资源实现互斥访问,并作为解决文件读写一致性问题的根本保障。在以只读方式访问文件为主的系统中,能够大大降低并发控制的时间开销和消息量。同时加入了节点失效和加锁进程失效检测机制,使得整个网络互斥锁的容错性能得到极大的改善。更多还原

【Abstract】 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.更多还原