【摘要】 副本技术广泛应用于分布式系统中,高效合理的副本放置对提高系统的可用性、可靠性,以及缩短用户访问时间都起到至关重要的作用.为了提高网络中副本的使用率,基于多访问策略,提出了一种性能较高的最远优先放置算法.通过引入了通信距离的限制,降低了客户访问时延,进而降低了整个系统访问时间,提高了访问效率.实验分析表明,与现有算法相比,提出的算法在最大使用每个副本处理能力的同时,大大降低了网络的运行成本.在不同的距离限制下,都得到了可观的改进,其中对现有算法的改进最高可达68%.更多还原

【Abstract】 Replica technology is widely applied in distributed systems.Efficient approaches for replica placement play a crucial role not only in improving availability,reliability of the systems,but also in reducing the user access time.Based on multi-access policy,this paper presents an efficient algorithm for replica placement with M ultiple Big Qo S Far Servers First,to increase the utilization of the replicas.M eanwhile,the proposed algorithm can produce the solution with lowlatency and high efficiency in customer access for systems,by adding the constraint of communication distance for the optimization problem.Experimental results showthat,the proposed algorithm successfully maximizes the processing capacity for each replica,while significantly reducing the running cost of the network under the different distance limits.The best improvement is up to 68% in comparison to the state-of-the-art.更多还原