【作者】 刘鑫；

【导师】 王凤先； 田俊峰；

【作者基本信息】 河北大学 ， 计算机应用技术， 2003， 硕士

【摘要】 近年来，人们对大规模分布式应用系统的要求不断提高，系统性能和可用性均已成为用户所追求的实现目标。为此，许多分布式应用采用了冗余服务技术：一方面，通过增加数据和计算的冗余度，提高了系统的可用性；另一方面，多个服务器并行地响应用户请求，提高了系统的性能。但冗余服务技术的引入也给系统的配置管理提出了新的挑战。因此，为了使冗余服务系统能够向用户提供高效快捷的服务，为之设计一套配置管理系统就显得尤为重要。 在分析传统配置管理系统不足的基础上，本文以性能、可用性、和扩展性为目标，对冗余服务的配置管理问题展开研究，提出了基于移动代理技术的适应性配置管理系统ACMS，它的主要技术特点如下： 采用层次化管理结构对冗余服务进行管理，改善了系统的可扩展能力，减小了通信开销。 从用户角度出发，采用基于性能索引的RoDO模型确定服务实例的冗余度，有效地权衡了客户对系统性能和可用性的需求； 结合可用性和性能两项指标，采用基于移动代理的配置管理策略对系统进行动态配置，在保证可用性的前提下，改善了系统性能，提高了资源利用率。 最后，本文基于CORBA计算平台对ACMS系统进行了原型实现，并对系统的通信开销和性能进行了分析和测试，验证了该系统的可行性。更多还原

【Abstract】 In recent years, the requirements of large-scale distributed system have increased gradually; system performance and availability are both the aims people pursuit. So, more and more distributed applications adopt redundant servers: on one hand, the system availability could be improved through adding the redundancy of data and computation; on the other hand, user requests are processed on several servers in parallel, so the system performance could be advanced by this means. However, the introduction of redundant servers results in the new challenges to the system configuration management. And it is clear that design a solution to the configuration management of redundant servers. Therefore, it is very important to design a configuration management system for redundant servers so that they could provide more efficient and more rapid service to users.On the basis of analyzing problems of traditional configuration management system, this thesis takes performance, availability and scalability as implement goals, discusses the configuration management for redundant servers, and proposes a mobile agent-based adaptive configuration management system. The features of system are as follow:(1) It adopts hierarchical management architecture to manage redundant servers, so the system scalability is improved and the system overhead is reduced.(2) It adopts RoDO model based on performance index to calculate the redundancy of instances, and this means can make tradeoff between user’s performance and availability demands effectively.(3) Form the viewpoint of system performance and availability, ACMS adopts mobile-agent technology to adjust system configuration in running time, improves system’s dynamic scalability and resource utilization ratio on condition of guaranteeing the system availability.In the end, a prototype of ACMS is implemented based on CORBA technology, and the overhead and performance of the system is evaluated to prove that ACMS is feasible.更多还原