【作者】 韩琳；

【导师】 盛翊智；

【作者基本信息】 华中科技大学 ， 控制理论与控制工程， 2007， 硕士

【摘要】 随着网络的普及,网络服务器需要为越来越多的用户提供服务,在这种情况下,即使单台服务器性能再高,所能提供的服务也是有限的,而且其工作量很容易在访问高峰时期过载。集群服务器结构能较好地解决上述问题,因此,研究集群服务器系统以及其负载均衡策略具有一定的理论意义和实用价值。论文从两个方面研究了集群服务器系统的性能,一是它的可靠性或可利用性;另一方面是它的吞吐率、响应时间、利用率等处理效率。阐述了Petri网的主要特性:并行、不确定性、异步和分布描述能力以及分析能力等。展示了Petri网除具有类似流程图、框图和网图的可视描述功能外,还可通过标记的流动模拟系统的动态、活动行为。论文以广东某公司的“分布式系统性能监测及反馈控制技术”项目为背景,在原项目单纯地从监测服务器负载大小来决定终端是否继续进行新请求的思想基础上,提出了在客户端与服务器端增添请求分配器的方法,将后端互为备用的服务器架构成集群结构。在此集群服务器系统中,将后端服务器所采用的请求调度优先级策略与请求分配器所使用的复杂均衡策略相结合的综合控制思想,实现负载均衡和QoS控制。并且采用随机高级Petri网性能功能模型与分析技术,对QoS-aware负载均衡策略的性能优越性进行了分析和研究。论文研究对象是负载均衡策略在集群服务器系统中的优化应用。在对系统的建模,模型仿真和性能评价方面所做的研究工作,对于同类系统建模及性能评价具有较好的借鉴作用。更多还原

【Abstract】 With the popularization of the network, the network servers have to provide more and more services for clients. Even the performance of a single server is high, the service which is provided by it is very limited. In visit peak period, the server is easily overloaded. Therefore, the cluster server system produced.As the ordinate computer system, the performance of the cluster server system includes two aspects: one is its reliability and usability, the other is its efficiency. There are three types included in efficiency. They are throughput, response time and utilization. Petri net is a useful graphics and math modeling tool which can be used in many systems and fields. Its characteristics include concurrency, nondeterminacy, asynchronism and distributed ability to describe and analyze. Petri nets have the functions as flowchart diagram and network map which can describe with visible method. It also can describe dynamic abilities of simulation systems with‘token’.The thesis’s background is the project named“the Performance Inspection and Feedback Control of Web-Service System”of a company. The thesis proposes integrated control idea, which adopts complex balancing strategy used in request distributor cooperating with priority of request used in servers. The thesis models cluster servers system based on the theory and technique of stochastic high-level Petri net, then analysis the performance of system.The research is to analysis and simulate the performance of the cluster server system, which is modeled with Petri net. This implements load balancing and QoS control of the system. It is very helpful for the related researches.更多还原