中文摘要：

针对云计算系统中的单点失效问题,提出一种云计算环境下的动态数据副本管理策略.该管理策略通过综合考虑目标放置节点的当前负载状况、可用存储空间大小、通信带宽以及其历史访问记录和历史失效记录等状态参数来进行数据文件的副本放置决策,并在进行副本置换操作时给予大尺寸数据文件副本更高的优先权.测试结果表明：该管理策略具有较为稳定的平均数据访问距离,且在云计算系统的负载均衡水平和平均任务执行时间指标上优于另外几种经典的副本策略.

英文摘要：

Focusing on the frequent single point of failure in cloud computer system,a dynamic data replica management strategy was proposed in cloud computer environment.The replica placement decision of the proposed replica management strategy was made by specifically analyzing the state parameters of target node,including the current load condition,the size of the current available storage capacity,the communication bandwidth,the historical access record and its historical failure record.And at the same time,a higher priority was provided to the bigger file replica in the decision-making of replica replacement.Experimental results illustrate that the proposed dynamic replica management strategy is stable in the criterion of average data access distance,and which outperforms other several classic replica strategy in the measurements of the system load balance level and the average task execution time.