共查询到17条相似文献,搜索用时 140 毫秒
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对等网络系统面临的最大的问题就是负载均衡.针对P2P网络中负载均衡的问题,提出了两种基于动态副本策略的负载均衡技术:周期性副本策略和基于需求的副本策略.在周期性副本策略里,每个超级节点周期性地把文件的副本发送给请求该文件频率最高的远程超级节点.在基于需求的副本策略里,当一个超级节点发现其对某个文件的访问频率过高时,就向拥有该文件的超级节点发送文件请求,以获得该文件副本.本文分析了这两种技术的平均访问代价和副本负载代价.一系列的模拟实验证实了这两种技术的可行性及其带来的好处. 相似文献
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副本技术是P2P网络中常用的一种数据管理机制,在P2P网络中,由于节点的高度动态性,致使副本管理也必须具有动态性,副本管理是一项极具研究价值的课题。如何利用副本技术来提高非结构化P2P网络的资源搜索效率仍是目前尚未有效解决的难点之一。对非结构化P2P网络中广泛应用的Gossip协议和副本管理策略进行了探索和研究,运用模糊理论提出一种副本存储节点的选择策略。通过模拟实验,对相关数据进行分析,证明该项研究能有效提高对等网络中资源搜索的效率。 相似文献
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P2P网中基于文件分片的副本建立策略* 总被引:1,自引:0,他引:1
在大规模P2P网络中,为了提高数据的可用性,可以通过在系统中多个节点上建立数据副本的方法来增加数据的冗余度.为了减小副本建立的开销,可采用一种基于文件分片的副本建立策略,将需要复制的数据文件先进行分片,然后把这些分片在一组选取好的候选节点间进行分发复制.该方法能够充分利用网络带宽,明显减小建立副本所需的时间开销. 相似文献
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With the growth of P2P file sharing systems, people are no longer satisfied with the sharing of the read-only and static files, and thus the systems with mutually writable and dynamic files have emerged, resulting in the replica inconsistency problem. To maintain the replica consistency, too many update messages need to be redundantly propagated due to the lack of the sharing of globally updated path information in the existing strategies. To address this problem, we propose an optimized strategy for update path selection, which makes the nodes share the update path information by using clone, variation and crossover operations for the update paths. We also present a repeated update strategy to cope with the churn problem so as to maintain replica consistency as far as possible even if some nodes temporarily leave the network. The simulation results show that our strategy can significantly reduce the number of the redundant update messages without lowering the message coverage, thus improving the availability of the unstructured P2P networks. 相似文献
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PATCOM:基于分割树的无结构P2P系统一致性维护方法 总被引:2,自引:0,他引:2
无结构P2P技术逐渐被应用在新型的协同计算系统中.这些新型业务支持数据的动态更新,不仅要求副本数据的强一致性,而且要求更新数据的快速传播.高效的一致性维护方法是保证新业务顺利开展的基础.在比较分析现有的P2P系统一致性维护方法的基础上,针对无结构P2P系统,提出了一种基于分割树的一致性维护方法--PATCOM.PATCOM使用Chord协议作为组管理协议,通过不断分割由副本节点组成的Chord环,动态地建立更新消息传播树(Update Message Propagation Tree,UMPT).论文进一步从理论上分析了UMPT的平均高度、PATCOM的性能、容错能力以及算法开销,并和基于Gossip的一致性维护方法进行了比较.理论分析和仿真实验结果表明:PATCOM不仅能够快速地维护P2P系统的强一致性,而且产生的冗余更新消息少. 相似文献
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副本定位技术是数据网格的关键技术。本文采用改进的Chord算法,同时借鉴了结构化P2P技术,提出了一种基于结构化P2P模式的副本定位方法。该方法能在一定程度上解决局域网间的“绕路”问题,提高了定位效率,节省了传输时间和带宽,优化了数据网格的性能。 相似文献
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Zhijun Wang Anwitaman Datta Sajal K. Das Mohan Kumar 《Journal of Parallel and Distributed Computing》2009
Peer-to-peer (P2P) has become a mainstream architecture in numerous diverse distributed applications. However current P2P systems do not provide consistency guarantees under multiple reader multiple writer scenarios. Such a feature is desirable as well as necessary for supporting more diverse applications than merely file-sharing systems. In this paper, we develop a highly scalable and efficient algorithm, called Consistency Maintenance through Virtual servers (CMV), in P2P systems. In this algorithm, consistency of each dynamic file is maintained by a Virtual Server (VS). A file update can only be accepted through the VS to ensure one-copy serializability consistency. The VS of a file is a logical network composed of multiple Replica Peers (RPs) that have replicas of the file. Mathematical analysis is performed for optimal parameter selections that achieve minimum overhead messages for maintaining file consistency. Simulation experiments are conducted to compare the performance of the proposed CMV algorithm with two existing schemes, namely the rumor spreading based scheme and the Update Propagation Through Replica Chain (UPTReC) scheme. Our results show that CMV can quickly commit update to the system and significantly reduce (by more than 90%) overhead messages compared to these schemes under various system conditions. 相似文献