个体QoS受限的数据网格副本管理与更新方法

数据网格系统通常采用副本技术提高系统总体性能,传统副本放置技术通过总体QoS需求确定副本数目和部署方式.针对QoS需求严格的一类数据网格应用,建立了个体服务质量受限的数据网格模型IQDG,提出一种启发式个体QoS受限的副本放置算法qGREP和基于逻辑环结构的一致性维护方法.IQDG采用的启发信息综合考虑了个体QoS约束的满足和副本开销的控制,能获得合理的副本策略.理论分析论证了算法的正确性和收敛性,模拟实验结果表明了算法能有效解决个体QoS受限的副本放置问题,在多种网络拓扑、访问模式和负载条件下均能取得较好的访问效果.

Replica Placement and Update Mechanism for Individual QoS-Restricted Requirement in Data Grids

As an important strategy for reducing access time,balancing overload,and obtaining high data availability,replication is widely used in distributed systems such as data grids.Currently grid researchers often consider replica management problem from the viewpoint of whole systems,ignoring individual QoS requirements of each single request.With the rapid growth of QoS-sensitive data grid applications,fulfilling QoS requirements of every request becomes a big challenge.In this paper,a new problem called indivi...