基于随机Petri网的P2P存储系统可靠性模型和分析  

Model and Analysis of Peer-to-Peer Storage System Reliability Based on Stochastic Petri Net

作　　者：刘志明[1,2] 沙基昌[1] 阳小华[2] 万亚平[2] 

机构地区：[1]国防科技大学信息系统与管理学院,长沙410073 [2]南华大学计算机应用研究所,衡阳421001

出　　处：《计算机科学》2011年第4期80-83,共4页Computer Science

基　　金：国家自然科学基金项目(70671051);国防基础研究课题(A3720060121)资助

摘　　要：可靠性是可信性研究的基本内涵之一,也是P2P(Peer-to-Peer)存储系统研究的关键。P2P存储系统结点具有高动态特征,结点频繁地上下线给系统的可靠性分析带来困难。结点的暂时离线会增加副本数量,从而导致系统不必要的损耗。较多的副本数量会增加系统的可靠性,但是同时会导致系统的一致性维护成本增加。而较少的副本数量又会导致系统的可靠性显著降低。针对副本的数量和可靠性之间的关系,采用随机Petri建立了P2P存储系统的可靠性模型并加以分析,围绕数据可靠性度量要求和数据副本的数量建立关系模型,从理论上指明研究系统可靠性的目的和基本原则,这可以在系统组建之初帮助优化系统的设计。Reliability is one of the basic connotations of dependability,and it is also the key of P2P Storage Systems study.P2P storage system nodes are highly dynamic.That nodes are from online to offline frequently will lead difficulty to system reliability analysis.If increasing the number of copies because nodes are temporarily offline,it will cause system to unnecessary outage.The larger number of copies will increase system reliability,but it will also cause the system to increase the cost of consistency maintenance.And the fewer number of copies will result in a significant reduction in reliability of the system.To address the problem of the quantity of copy and system reliability,a reliability model of P2P storage system which revolved around relationships between the requirements of data reliability measurement and the number of copies was built by stochastic Petri nets（SPN） and used to analysis.It identified the purpose and basic principles of studying system reliability from theory and can help to optimize the system design on early stage.

关 键 词：随机PETRI网 P2P存储系统 可靠性 副本冗余 

分 类 号：TP302.7[自动化与计算机技术—计算机系统结构]