摘要
可用性是存储系统最重要的属性之一,由于节点的复杂活动,使得在P2P存储系统中的可用性保证变得很困难.试图为系统中所有用户提供无差别的高可用服务是不切实际的,并提出了一个分层次的差异型P2P存储体系,其基本思路是对节点的分层次组织和有差异服务,即一方面不再从整体上组织节点,而是依照节点的特点分层次组织;另一方面,不再提供无差别服务,而是依照节点的贡献提供差别服务,这既简化了大规模节点组织的复杂性,又提供了激励机制,使得在极为动态和不可靠的环境下实现一个具有高可用性的大规模P2P存储系统成为可能.首先给出节点活动的更精确模型,然后提出3种节点组织策略,并用实验分析它们的适用范围和随层次变化的趋势,最后总结确定不同层次上的可用性保证策略.
Availability is one of the most important properties of a storage system. However, it is very difficult to guarantee availability in P2P storage system because of peer churn. This paper argues that it is unfeasible to provide the same availability level to all peers, so it presents a novel P2P storage architecture which builds on the basis of hierarchical management and differentiated service. This architecture has two important characters： First it uses a hierarchical organization according to peers＇ character instead of organization as a whole; second, it provides different availability according to peer＇s contribution instead of an unbiased service. This not only simplifies the organization of large-scale peers, but also provides a good incentive mechanism. This paper firstly presents a more precise peer behavior model, and then proposes three peer organization strategies and examines their efficiency On different hierarchy in order to study their applicable scopes. Finally, it summarizes the strategies of keeping availability in different hierarchies.
出处
《软件学报》
EI
CSCD
北大核心
2007年第10期2481-2494,共14页
Journal of Software
基金
Supported by the National Basic Research Program of China under Grant No.2004CB318204 (国家重点基础研究发展计划(973))
