Abstract: To improve the running efficiency of business workflow in cloud environment, a policy of replica allocation of cloudy services was proposed. Taking the advantage of social network analysis, the policy specified the central service nodes in a service network based on mining the social network properties such as connectivity and centralization for a service community. The host physical machine of the replica of the central service was specified according to the analysis of logical sequence between the central service and its pre-service, and the usage of other physical machines. The analysis and simulation show that the policy can improve the running efficiency of data intensive business workflow in a cloud environment by averaging the overload of physical machine and reducing the time wasted by long-distance service interaction.

Key words: cloud computing, service replica, business workflow, social network, centralization, pre-allocation

摘要： 为提高云环境下业务流程的执行效率，提出一种云服务副本放置策略。该策略基于社会网络分析的思想，挖掘出云服务社区中服务网络的连通性、中心化等社会网络特征，从而确定服务网络中处于枢纽位置的中心服务节点。通过分析中心服务节点和其前驱节点的逻辑序列关系，结合服务节点所在物理机的负载情况，确定中心服务节点的副本的宿主物理机并进行预放置。实验结果表明，该策略可以减少云环境中的业务流程因异地服务的交互造成的时间消耗，均衡节点负载，提高业务流程的执行效率。

关键词: 云计算, 服务副本, 业务流程, 社会网络, 中心化, 预放置