服务器负载均衡(Server Load Balancing)在企业中的应用

一般的服务器组中的服务器只能保持其中一台工作,以确保企业工作的正常开展,效率不太高。而服务器负载均衡技术不仅可以保证服务器24h不停运作,在单个服务器出现问题时不影响现有业务的处理,可以使正常的切换基本达到无缝连接。服务器负载均衡技术是将一组服务器用一台独立的服务器的虚拟形式表现,用户在应用时只看到一个虚拟服务器,当客户端设置一个连接到虚拟服务器IP地址的连接时,服务器负载均衡算法选择一个合适的实际服务器来连接。可通过一些命令来实现这一技术。

Adaptive Server Load Balancing in SDN Using PID Neural Network Controller

Web service applications are increasing tremendously in support of high-level businesses.There must be a need of better server load balancing mechanism for improving the performance of web services in business.Though many load balancing methods exist,there is still a need for sophisticated load bal-ancing mechanism for not letting the clients to get frustrated.In this work,the ser-ver with minimum response time and the server having less traffic volume were selected for the aimed server to process the forthcoming requests.The Servers are probed with adaptive control of time with two thresholds L and U to indicate the status of server load in terms of response time difference as low,medium and high load by the load balancing application.Fetching the real time responses of entire servers in the server farm is a key component of this intelligent Load balancing system.Many Load Balancing schemes are based on the graded thresholds,because the exact information about the networkflux is difficult to obtain.Using two thresholds L and U,it is possible to indicate the load on particular server as low,medium or high depending on the Maximum response time difference of the servers present in the server farm which is below L,between L and U or above U respectively.However,the existing works of load balancing in the server farm incorporatefixed time to measure real time response time,which in general are not optimal for all traffic conditions.Therefore,an algorithm based on Propor-tional Integration and Derivative neural network controller was designed with two thresholds for tuning the timing to probe the server for near optimal perfor-mance.The emulation results has shown a significant gain in the performance by tuning the threshold time.In addition to that,tuning algorithm is implemented in conjunction with Load Balancing scheme which does not tune thefixed time slots.

Load Balancing Based on Multi-Agent Framework to Enhance Cloud Environment

According to the advances in users’service requirements,physical hardware accessibility,and speed of resource delivery,Cloud Computing(CC)is an essential technology to be used in many fields.Moreover,the Internet of Things(IoT)is employed for more communication flexibility and richness that are required to obtain fruitful services.A multi-agent system might be a proper solution to control the load balancing of interaction and communication among agents.This paper proposes a multi-agent load balancing framework that consists of two phases to optimize the workload among different servers with large-scale CC power with various utilities and a significant number of IoT devices with low resources.Different agents are integrated based on relevant features of behavioral interaction using classification techniques to balance the workload.Aload balancing algorithm is developed to serve users’requests to improve the solution of workload problems with an efficient distribution.The activity task from IoT devices has been classified by feature selection methods in the preparatory phase to optimize the scalability ofCC.Then,the server’s availability is checked and the classified task is assigned to its suitable server in the main phase to enhance the cloud environment performance.Multi-agent load balancing framework is succeeded to cope with the importance of using large-scale requirements of CC and(low resources and large number)of IoT.

可扩展并行Web Server集群技术

采用并行Ｗｅｂ Ｓｅｒｖｅｒ 集群技术实现高性能Ｗ ｅｂ Ｓｅｒｖｅｒ已经成为一种趋势． 该技术具有性能高、可扩展性好、可靠性高、成本低等优点． 本文介绍了我们研制的ＴＨＷｅｂ Ｃｌｕｓｔｅｒ的工作原理、组成结构和所采用的几种关键技术， 并与现有的技术和方法进行了比较． 本文还简要介绍了ＴＨＷｅｂ Ｃｌｕｓｔｅｒ 上开发的两个应用系统ＴＨＷｅｂ Ｄｉｇｇｅｒ（信息挖掘工具）和ＴＨＷ ｅｂ Ｓｅａｒｃｈ（搜索引擎）， 并以此说明Ｗ ｅｂ Ｓｅｒｖｅｒ

Web-Server集群结构与多任务实时调度的应用研究

探讨了开发Web-Server集群系统所需要解决的主要技术问题,以及当前计算机领域中的部分研究成果,并结合实际应用的需要,讨论了Web-Server集群技术在基于Web的电工电子实验系统中的应用,给出了该系统的结构模型,并详细分析了所采取的有效的任务实时调度策略,进行了算法描述。结合所采用的动、静态任务调度算法,实现了基于集群的远程实验系统的开发,获得了良好的教学和科研效果。

HTTP多路超链接在Web Servers中的应用

频繁的ＷＷＷ访问要求有有效的Ｗｅｂ Ｓｅｒｖｅｒｓ组织方式。针对ＨＴＴＰ超链接不能进行负载平衡的缺点，提出了ＨＴＴＰ多路超链接，并用ＨＴＴＰ超链接对ＨＴＴＰ多路超链接进行了模拟。最后将ＨＴＴＰ多路超链接引入Ｗｅｂ Ｓｅｒｖｅｒｓ设计。

基于“伪HTTP Server”的CDN本地负载均衡实现方式

为解决CDN中的本地负载均衡问题,文中首先介绍了基于HTTP重定向的负载均衡技术,接下来以此为启示提出并设计实现了一种基于伪HTTP Server的本地负载均衡实现方式。基于伪HTTP Server方式主要是通过构造一个HTTP响应,即设置一个"伪HTTP Server",并基于相应的HTTP重定向策略来对用户请求进行重新导向,以实现将用户的请求导向到性能最佳的节点。测试数据表明,该方式能够大大减轻CDN中各服务器节点的负担,快速有效地解决网络堵塞的问题,提高了用户访问网站的响应速度。

基于Windows 2003 Server的负载均衡技术

负载均衡技术是提高服务器工作能力和效率的关键技术。目前存在的负载均衡技术各有优点,而服务器群集化使得网络负载均衡能力得到极大改善,在Windows2003Server中集成了基于服务器群集化的网络负载均衡功能,该系统易于操作实现。

SLB技术在应用系统平台建设中的研究——以西方宗教音乐资源检索平台建设为例

阐述了服务器负载均衡(SLB)技术的工作原理,提出了应用其特性来保证西方宗教音乐资源检索平台运行的可靠性和减轻单台服务器工作压力的方案,并给出了不同工作模式下的详细配置命令。仿真测试证明该方案有效实用,在设备运行正常情况下,各服务器之间实现流量负载均衡,对于用户的服务请求会分别响应。当某台服务器发生故障,其他服务器会继续响应用户的服务请求,在此过程中用户丝毫不会感觉到服务器故障的发生。

Web Server集群技术

以LVS为例构建了一个集群系统 ,对部分LVS核心程序进行了修改 ,并加入了一种新的分配算法 。

Load-Balance Policy in Two Level-Cluster File System

In this paper, we explored a load-balancing algorithm in a cluster file system contains two levels of metadata-server, primary-level server quickly distributestasks to second-level servers depending on the closest load-balancing information. At the same time, we explored a method which accurately reflect I/O traffic and storage of storage-node： computing the heat-value of file, according to which we realized a more logical storage allocation. According to the experiment result, we conclude that this new algorithm shortens the executing time of tasks and improves the system performance compared with other load algorithm.

一种多控制器的网络服务器集群负载均衡调度策略

为提高网络服务器集群中心宽带利用率、降低网络访问及传输时延,文章提出一种基于SDN的多控制器负载均衡调度策略。首先,构建多控制器的网络服务器集群负载均衡调度的总体框架,通过转发层采集网络交换设备的状态信息;然后,在多控制器单元生成全局网络视图,采用自适应网络大小流进行调度,以提高网络及传输时延为目标构建网络服务器集群负载均衡调度策略模型。最后,控制器单元更新流量表并对OpenFlow交换层设备进行更新,以实现网络服务器集群中心的网络负载均衡。

车联网中基于多智能体强化学习的边缘服务器选址策略

为解决车联网环境下边缘服务器选址难的问题,提出一种基于多智能体强化学习的边缘服务器部署策略(记为CKM-MAPPO),重点优化边缘服务器间的负载均衡,同时最小化边缘服务器的时延和能耗。首先,使用Canopy和K-means算法确定边缘服务器部署的数量和初始位置;然后,基于多智能体强化学习算法确定边缘服务器的最优部署位置;最后,通过一系列实验评估所提出算法的准确性和有效性。研究结果表明:与基准算法相比,本文提出的方法的负载均衡度提升了26.5%,时延和能耗分别降低了12.4%和17.9%。

An Efficient Load Balancing Approach for N-Hierarchical Web Server Cluster

Aiming at the load imbalance and poor scalability in single-tier Web server clusters, an efficient load balancing ap- proach is proposed for constructing an N-hierarchical （multi-tier） Web server cluster. In each layer, multiple load balancers are set to receive the user requests simultaneously, and different load bal- ancing algorithms are used to construct the high-scalable Web cluster system. At the same time, an improved load balancing al- gorithm is proposed, which can dynamically calculate weights according to the utilization of the server resources, and reasonably distribute the loads for each server according to the load status of the servers. The experimental results show that the proposed ap- proach can greatly decrease the load imbalance among the Web servers and reduce the response time of the entire Web cluster system.

Dynamic weighted random load balancing algorithm for SIP application server

A new load balancing algorithm named dynamic weighed random （DWR） algorithm for the session initiation protocol （SIP） application server cluster is proposed. It uses weighted hashing random algorithm that supports dialog in the SIP protocol to distribute messages. The weight of each server is dynamic adaptive with feedback mechanism. DWR insures that the cluster is balanced, and it performs better than the limited resource vector （LRV） algorithm and minimum sessions first （MSF） algorithm.

基于OpenResty的一种自定义负载均衡算法

为了解决服务器集群中负载调度不均衡导致高并发情况下服务器响应时间过长以及实际并发数过低的问题,提出一种基于加权轮询算法以及层次分析法(Analystic Hierarchy Process,AHP)的自定义请求类型负载均衡算法。首先收集服务器集群的负载信息,其次定时与负载均衡服务器通信,同步集群节点的负载情况,最后根据请求类型使用对应的权重。实验结果表明,文章提出的算法能够有效应对高并发情形。

多线程多核服务器功耗模型及性能监控

针对现有服务器的CPU功耗准确性不足和多线程处理功耗负载不平衡问题,本文提出了一种多线程和多核服务器CPU功耗模型。该模型采用前后端分离的整体架构思想,根据服务器功耗模型实时获取CPU的线程数、频率及利用率。通过日志文件进行反馈多线程和多核功耗模型,达到最佳服务器负载平衡。仿真测试的结果表明,改进的服务器功耗模型在CPU利用率方面比传统服务器提高了6%,内存以及I/O通信方面也有明显改善,为多线程和多核服务器提供了一种新的功耗模型思路。

移动边缘计算网络中基于任务转移的负载均衡优化方案

针对MEC服务器之间的负载不均衡问题,论文提出了一种基于任务转移的负载均衡算法。该算法在考虑任务转移时延的前提下,确定是否将任务转移至其他MEC服务器,并在当前时隙结束时做出最优的任务转移决策。实验结果表明,提出方案的性能优于其他方案,使得MEC服务器之间的负载更加均衡。

医院服务器集群基于NGINX的综合应用

目的:利用Nginx在服务应用方面的优势,改善现有医院服务器群存在的问题,并进一步提升医院服务器集群在应用服务方面的性能和安全指数。方法:本研究梳理了当前医院应用服务器群存在的问题,通过实践与探索,利用Nginx的反向代理和负载均衡技术对医院服务器群的结构进行改造,搭建了一个高可用性、安全性的服务器集群。接着,通过分析Nginx日志和服务器监控数据,对服务器集群策略进行进一步的优化。结果:与原医院服务器群相比,新的医院服务器集群在稳定性、安全性和可用性等方面都有了极大的提升。结论:与传统的应用服务器架构相比,利用Nginx搭建的服务器集群可以提高医院应用服务的高可用性,保障医院应用服务的平均无故障时间。

基于Nginx的动态权重负载均衡技术研究

负载均衡策略在保障Web服务器集群稳定运行和性能方面是不可或缺的。在众多的负载均衡技术中,Nginx得到了广泛应用,常被大规模应用于反向代理服务前端。通过对Nginx负载均衡算法的学习研究,设计实现了一种改进的动态权重负载均衡算法。该算法利用Redis缓存机制,实时采集并存储后端Web服务器的CPU利用率、内存利用率、网络带宽和磁盘I/O等性能指标信息。然后,通过熵值法计算各项性能指标的系数,并动态地修改后端Web服务器的权重。实验结果显示,与加权轮询算法和最小连接数算法相比,新算法在高并发情况下具有更好的响应时间和吞吐量。