基于Chord网络模型的改进数据复制方法

根据现有复制策略在局部节点故障时数据查找失败率高的缺点,提出一种针对Chord网络的数据复制方法——Rd-Chord(rearranged replication method based on Chord).利用离散存储的方法,将数据复制到Chord覆盖网根节点前继相对分散的节点中,即使某个甚至几个区域节点全部故障,其他区域依然有数据副本可供使用.同时,为了维护网络结构和key迁移,针对Rd-Chord提出基础更新和定期更新2种更新策略.为了验证该方法的优越性,通过计算机仿真对前继复制、后继复制和Rd-Chord方法进行了大量的比较实验.实验结果表明,Rd-Chord方法能够解决节点区域性故障问题,在保证平均查找效率的前提下,查找失败率降低了近10％,明显优于其他方法.

Improved data replication approach based on Chord network model

To solve the high failure rate in data search under the local node failure of the existing replication strategy,a new data replication mechanism called Rd-Chord is proposed.Discrete storage method is employed to deal with the data copies' storage in the relatively decentralized nodes which are Pre-relay nodes of the root node in the Chord network,and thus there are still copies of data available in other regions even if all the nodes in one region or several regions are breakdown.Simultaneously,a basic update strategy and a periodic update strategy for Rd-Chord are presented to maintain the network structure and key migration.In order to verify the superiority of this method,the extensive comparative experiments on the existing predecessor replication,successor replication,and Rd-Chord are carried out,and the experiment results show that Rd-Chord is superior to the other methods in terms of the capability of solving the regional node failure,the searching failure rate of Rd-Chord is also cut down about 10％ but the average searching efficiency is ensured.