文章在对机群系统的运行特性进行分析的基础上，运用马氏过程描述了机群系统中的高可用性（ High Availability），并从理论上建立了基于生灭过程的机群高可用模型。文中在给出机群高可用管理软件结构的基础上，设计了一种基于集中式结...文章在对机群系统的运行特性进行分析的基础上，运用马氏过程描述了机群系统中的高可用性（ High Availability），并从理论上建立了基于生灭过程的机群高可用模型。文中在给出机群高可用管理软件结构的基础上，设计了一种基于集中式结构的主副容错协议；通过可用度的分析结果得出：机群高可用系统采用了可修复性技术后，只要有一个 HA节点能正常工作，该系统是“可用”的。展开更多
Failures are normal rather than exceptional in the cloud computing environments. To improve system avai- lability, replicating the popular data to multiple suitable locations is an advisable choice, as users can acces...Failures are normal rather than exceptional in the cloud computing environments. To improve system avai- lability, replicating the popular data to multiple suitable locations is an advisable choice, as users can access the data from a nearby site. This is, however, not the case for replicas which must have a fixed number of copies on several locations. How to decide a reasonable number and right locations for replicas has become a challenge in the cloud computing. In this paper, a dynamic data replication strategy is put forward with a brief survey of replication strategy suitable for distributed computing environments. It includes： 1） analyzing and modeling the relationship between system availability and the number of replicas; 2） evaluating and identifying the popular data and triggering a replication operation when the popularity data passes a dynamic threshold; 3） calculating a suitable number of copies to meet a reasonable system byte effective rate requirement and placing replicas among data nodes in a balanced way; 4） designing the dynamic data replication algorithm in a cloud. Experimental results demonstrate the efficiency and effectiveness of the improved system brought by the proposed strategy in a cloud.展开更多
文摘文章在对机群系统的运行特性进行分析的基础上，运用马氏过程描述了机群系统中的高可用性（ High Availability），并从理论上建立了基于生灭过程的机群高可用模型。文中在给出机群高可用管理软件结构的基础上，设计了一种基于集中式结构的主副容错协议；通过可用度的分析结果得出：机群高可用系统采用了可修复性技术后，只要有一个 HA节点能正常工作，该系统是“可用”的。
基金Supported by the National Natural Science Foundation of China under Grant Nos. 61070162, 71071028 and 70931001the Specialized Research Fund for the Doctoral Program of Higher Education of China under Grant Nos. 20110042110024 and 20100042110025the Fundamental Research Funds for the Central Universities of China under Grant Nos. N100604012, N090504003 and N090504006
文摘Failures are normal rather than exceptional in the cloud computing environments. To improve system avai- lability, replicating the popular data to multiple suitable locations is an advisable choice, as users can access the data from a nearby site. This is, however, not the case for replicas which must have a fixed number of copies on several locations. How to decide a reasonable number and right locations for replicas has become a challenge in the cloud computing. In this paper, a dynamic data replication strategy is put forward with a brief survey of replication strategy suitable for distributed computing environments. It includes： 1） analyzing and modeling the relationship between system availability and the number of replicas; 2） evaluating and identifying the popular data and triggering a replication operation when the popularity data passes a dynamic threshold; 3） calculating a suitable number of copies to meet a reasonable system byte effective rate requirement and placing replicas among data nodes in a balanced way; 4） designing the dynamic data replication algorithm in a cloud. Experimental results demonstrate the efficiency and effectiveness of the improved system brought by the proposed strategy in a cloud.
