中文摘要：

结构化P2P系统通常使用数据复制来提高数据可用性,但P2P环境中的节点搅动、多节点并发更新以及恶意节点的存在也为副本的一致性管理带来了新的挑战.基于协商的算法要求节点间以全交换的方式通讯,在P2P环境中其可伸缩性不够理想.本文针对结构化P2P系统提出一种基于Quorum的副本管理算法：使用混合失效模型降低容错开销,利用DHT服务处理节点搅动,将数据存储与其元信息管理分离,使数据可靠性和数据可用性得以独立调整.模拟实验表明该算法可以明显改善系统的可伸缩性,减少系统的容错开销.

英文摘要：

To ensure high data availability,structured P2P systems typicallyrely on data replication.However,nodes churn,concurrent updates and existence of malicious nodes in P2P environments bring new challenges to the consistency management of replicas.Agreement-based algorithms require all-to-all communication among nodes,which does not scale well in P2P environment.Regards to structured P2P systems,a Quorum based replica consistency management algorithm is proposed.Hybrid failure model is used to reduce the fault-tolerant cost,DHT service is used to handle churn,and data storage and metadata management are separated to enable data reliability and data availability to adjust independently.Simulation shows the proposed algorithm can obviously improve system scalability and reduce the fault-tolerant cost.