共查询到19条相似文献,搜索用时 128 毫秒
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近年来,Web服务器集群技术以其扩展性好、处理能力强等优点受到了国内外研究机构的广泛关注和应用,其中的负载均衡算法更是研究的热点;对Web服务器集群负载均衡进行了研究,为有效地实现任务的均衡分配,提出一种了根据Web服务器系统中各个服务器的负载情况进行动态任务分配的遗传算法,实验表明该方法能有效地实现Web服务器集群的负载均衡服务。 相似文献
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基于预测机制的自适应负载均衡算法 总被引:1,自引:0,他引:1
工作负载特征对Web服务器集群中负载均衡调度算法的性能有重要影响。针对负载特征在调度算法所起作用的分析和讨论,提出基于预测机制的自适应负载均衡算法(RR_MMMCS-A-P)。通过监测工作负载,预测后续请求到达率和请求大小,快速调整相应参数,实现集群中各服务器之间的负载均衡。实验表明,无论是对计算密集型任务还是数据密集型任务,RR_MMMCS-A-P同基于CPU和CPU-MEM的调度算法相比在缩短平均响应时间方面具有较好的性能。 相似文献
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近年来,Web技术得到了长足的发展,Web集群系统对于Internet体系来说变得越来越重要。如何均衡地分配客户端发来的请求,如何平衡Web集群中各服务器之间的负载成为一个研究热点。文章设计和实现了一个负载均衡软件,可以用来很好地解决这些问题,测试结果证明该软件具有很高的实用价值。 相似文献
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Web集群系统负载均衡策略分析与研究 总被引:8,自引:4,他引:8
Web集群技术是解决Web服务器系统容量和伸缩能力的重要方法。该文分析了影响Web集群系统性能的主要因素,并提出了一种基于内容的负载均衡算法。该算法以加权负载量来评估服务器负载状态,并通过保证负载局部性来提高cache命中率,从而获得好的负载均衡效果。仿真实验证明,该算法具有较好的适应能力和伸缩性。 相似文献
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基于遗传算法的Web服务器集群负载均衡研究 总被引:1,自引:0,他引:1
近年来,Web服务器集群技术以其扩展性好、处理能力强等优点受到了国内外研究机构的广泛关注,其中的负载均衡算法更是研究的热点。本文对web服务器集群负载均衡进行了研究。为有效地实现任务的均衡分配,提出一种了根据web服务器系统中各个服务器的负载情况进行动态任务分配的遗传算法。实验表明该方法能有效地实现web服务器集群的负载均衡服务。 相似文献
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Web集群服务器已被广泛用来提高Web服务器的性能。对于如今内容海量级的大型网站来说,如何在Web集群服务器上组织和分布Web文档是一个急需解决的问题。本文提出了一种Web集群服务器中文档组织和分布的优化策略,其目是减少集群系统的平均响应时间。通过对Web服务器日志的分析,挖掘客户的访问模式,将关联度高的网页聚类成网页簇,然后根据网页簇的负载计算其拷贝份数,最后在集群中优化分布各网页簇的拷贝。以这种方法组织和分布文档,可以减少服务器端的TCP连接迁移开销,可以实现集群内的负载均衡,从而减小集群系统的平均响应时间;且相对于内容全镜像的文档分布方案,节约了存储空间,减少了维护各服务器文档一致性的开销。 相似文献
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Web服务器组的负载均衡方法研究 总被引:14,自引:0,他引:14
服务器组是大中型网站建设的重要架构。本文讨论了服务器组的组成模式及其组成结构,针对目前服务器组使用的负载均衡方法所存在的缺陷:未真正考虑到服务器组的当前负载,提出两种新的负载均衡算法,即负载最小优先算法和混合负载均衡算法。实验结果表明,新方法可更有效地均衡服务器组的负载。 相似文献
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《Computer Networks》1999,31(11-16):1215-1229
Traditional techniques for a distributed web server design rely on manipulation of central resources, such as routers or DNS services, to distribute requests designated for a single IP address to multiple web servers. The goal of the distributed cooperative Web server (DCWS) system development is to explore application-level techniques for distributing web content. We achieve this by dynamically manipulating the hyperlinks stored within the web documents themselves. The DCWS system effectively eliminates the bottleneck of centralized resources, while balancing the load among distributed web servers. DCWS servers may be located in different networks, or even different continents and still balance load effectively. DCWS system design is fully compatible with existing HTTP protocol semantics and existing web client software products. 相似文献
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为了提高网格服务器的性能,研究和设计了基于分配器的网格服务器性能优化系统,并实现了一个原型系统——集群式网格服务器.该原型系统能够集成多个网格处理服务器的处理能力,提供一个单一映象的网格服务.在这些服务器上实现负载平衡,并通过分配器统一对外提供网格服务.测试并分析了CGSS系统的性能测试结果.测试结果表明,基于分配器的性能优化能够显著的提高网格服务器系统的性能. 相似文献
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Saeed Sharifian Seyed A. Motamedi Mohammad K. Akbari 《The Journal of supercomputing》2010,53(3):440-463
The growth of web-based applications in business and e-commerce is building up demands for high performance web servers for
better throughputs and lower user-perceived latency. These demands are leading to a widespread substitution of powerful single
servers by robust newcomers, cluster web servers, in many enterprise companies. In this respect the load-balancing algorithms
play an important role in boosting the performance of cluster servers. The previous load-balancing algorithms which were designed
for the handling of static contents in web services suffer from significant performance degradation under dynamic and database-driven
workloads. Regarding this, we propose an approximation-based load-balancing algorithm with admission control for cluster-based
web servers in this study. Since it is difficult to accurately determine the loads of web servers through feedbacks from distributed
agents in web servers, we propose an analytical model of a web server to estimate the web servers’ loads. To achieve this,
the algorithm classifies requests based on their service times and track numbers of outstanding requests for each class of
each web server node and also based on their resource demands to dynamically estimate the loads of each node. For the error
handling of the model a proportional integral (PI) controller from control theory is used. Then the estimated available capacity
of each web server is used for load balancing and admission control decisions. The implementation results with a standard
benchmark confirm the effectiveness of the proposed scheme, which improves both the mean response time and the throughput
of the cluster compared to rival load-balancing algorithms, and also avoids situations in which the cluster is overloaded,
even when the request rates are beyond the cluster capacity. 相似文献
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With the exponential growth of WWW traffic, web proxy caching becomes a critical technique for Internet web services. Well-organized
proxy caching systems with multiple servers can greatly reduce the user perceived latency and decrease the network bandwidth
consumption. Thus, many research papers focused on improving web caching performance with the efficient coordination algorithms
among multiple servers. Hash based algorithm is the most widely used server coordination mechanism, however, there's still
a lot of technical issues need to be addressed. In this paper, we propose a new hash based web caching architecture, Tulip.
Tulip aggregates web objects that are likely to be accessed together into object clusters and uses object clusters as the
primary access units. Tulip extends the locality-based algorithm in UCFS to hash based web proxy systems and proposes a simple
algorithm to reduce the data grouping overhead. It takes into consideration the access speed dispatch between memory and disk
and replaces expensive small disk I/O with less large ones. In case a client request cannot be fulfilled by the server in
the memory, the system fetches the whole cluster which contains the required object into memory, the future requests for other
objects in the same cluster can be satisfied directly from memory and slow disk I/Os are avoided. It also introduces a simple
and efficient data dupllication algorithm, few maintenance work need to be done in case of server join/leave or server failure.
Along with the local caching strategy, Tulip achieves better fault tolerance and load balance capability with the minimal
cost. Our simulation results show Tulip has better performance than previous approaches. 相似文献
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CCSAS:一个高效灵活的应用服务器集群通信系统 总被引:1,自引:0,他引:1
可靠的集群通信系统为Web应用服务器集群在高负载条件下满足性能需求提供了基础.本文分析了利用集群技术扩展Web应用服务器对于通信的关键需求,提出了一个高效、灵活的集群通信系统,阐述了该系统的结构和设计,介绍了其中若干关键技术和解决办法,包括多播消息的高效传递、协议层次、可配置集群拓扑结构和备份模式等.本文描述的集群通信系统已在自主研发的OnceAS应用服务器中实现. 相似文献
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集中管理式Web缓存系统及性能分析 总被引:5,自引:0,他引:5
共享缓存文件是减少网络通信量和服务器负载的重要方法,本文在介绍Web Caching技术及流行的Web缓存通信协议ICP的基础上,提出了一种集中管理式Web缓存系统,该系统通过将用户的HTTP请求,按照一定的算法分发到系统中某一合适的缓存服务器上,从而消除了缓存系统内部服务器之间庞大的通信开销及缓存处理负担,减少了缓存内容的冗余度.通过分析,证明了集中管理式Web缓存系统比基于ICP的简单缓存系统具有缓存效率高、处理开销低、延迟小等优点,并且该系统具有良好的可扩展性. 相似文献