检索结果-内蒙古大学图书馆

A predictive and probabilistic load-balancing algorithm for cluster-based web servers

APPLIED SOFT COMPUTING 2011年第1期11卷 970-981页

作者： Sharifian, Saeed Motamedi, Seyed A. Akbari, Mohammad K. Amirkabir Univ Technol Dept Elect Engn Tehran 15914 Iran Amirkabir Univ Technol Dept Comp Engn & IT Tehran 15914 Iran

The exponential demands for high performance web servers led to use of cluster-based web servers. This increasing trend continues as dynamic contents are changing traditional web environments. Increasing utilization of cluster web servers through effective and fair load balancing is a crucial task specifically when it comes to advent of dynamic contents and database-driven applications on the internet. The proposed load-balancing algorithm classifies requests into different classes. The algorithm dynamically selects a request from a class and assigns the request to a server. For both the scheduling and dispatching, new probabilistic algorithms are proposed. To avoid using unreliable measured utilization in the face of fluctuating loads the proposed load-balancing algorithm benefits from a queuing model to predict the utilization of each server. We also used a control loop feedback to adjust the predicted values periodically based on soft computing techniques. The implementation results, using standard benchmarks confirms the effectiveness of proposed load-balancing algorithm. The algorithm significantly improves both the throughput and mean response time in contrast to two existing load-balancing algorithms. (c) 2010 Elsevier B. V. All rights reserved.

关键词： cluster-based web server Dynamic load-balancing Layer-7 web-switch Scheduling RBF network ANFIS network

来源：评论

学校读者我要写书评

暂无评论

Elastic management of web server clusters on distributed virtual infrastructures

引用

CONCURRENCY AND COMPUTATION-PRACTICE & EXPERIENCE 2011年第13期23卷 1474-1490页

作者： Moreno-Vozmediano, Rafael Montero, Ruben S. Llorente, Ignacio M. Univ Complutense Madrid Distributed Syst Architecture Res Grp E-28040 Madrid Spain

cluster-based solutions are being widely adopted for implementing flexible, scalable, low-cost and high-performance web server platforms. One of the main difficulties to implement these platforms is the correct dimensioning of the cluster size, so as to satisfy variable and peak demand periods. In this context, virtualization is being adopted by many organizations as a solution not only to provide service elasticity, but also to consolidate server workloads, and improve server utilization rates. A virtualized web server can be dynamically adapted to the client demands by deploying new virtual nodes when the demand increases, and powering off and consolidating virtual nodes during periods of low demand. Furthermore, the resources from the in-house infrastructure can be complemented with a cloud provider (cloud bursting), so that peak demand periods can be satisfied by deploying cluster nodes in the external cloud, on an on-demand basis. In this paper, we analyze the scalability of hybrid virtual infrastructures for two different distributed web server cluster implementations: a simple web cluster serving static files and a multi-tier web server platform running the Cloud Stone benchmark. Copyright (C) 2011 John Wiley & Sons, Ltd.

关键词： cluster-based web server virtualization cloud computing cloud bursting

来源：评论

学校读者我要写书评

暂无评论

An approximation-based load-balancing algorithm with admission control for cluster web servers with dynamic workloads

引用

JOURNAL OF SUPERCOMPUTING 2010年第3期53卷 440-463页

作者： Sharifian, Saeed Motamedi, Seyed A. Akbari, Mohammad K. Amirkabir Univ Technol Dept Elect Engn Tehran 15914 Iran Amirkabir Univ Technol Dept Comp Engn & IT Tehran 15914 Iran

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.

关键词： cluster-based web server Dynamic load-balancing algorithm Admission control Analytical model of web server Feedback controller design

来源：评论

学校读者我要写书评

暂无评论

Modeling and simulation of performance analysis for a cluster-based web server

引用

SIMULATION MODELLING PRACTICE AND THEORY 2006年第2期14卷 188-200页

作者： Yang, JH Jin, D Li, Y Hielscher, KS German, R China Agr Univ Coll Informat & Elect Engn Beijing 100083 Peoples R China Univ Erlangen Nurnberg Dept Comp Sci D-91058 Erlangen Germany

Higher scalability and availability of web servers are required as the traffic on the Internet has been increasing dramatically over the last few years, This paper focuses on modeling and simulation of the performance analysis for the test System of a cluster-based web server consisting of five real servers. Three ways of load balancing are introduced, namely, network address translation, IP tunneling and direct routing. Calculation of packet delay is discussed for each part of the running system according to the transferred data in the system, The input model and the system model to measure and simulate the system performance are derived, and the probability distributions of the delay data are specified for using random inputs in the model according to the Q-Q plot and the cumulative distribution function, After the solution of performance tuning problems is evaluated, the maximum process capability Of the system is found and a possible performance bottleneck is analyzed, (c) 2005 Elsevier B.V. All rights reserved.

关键词： cluster-based web server system simulation modeling load balancing performance probability distribution

来源：评论

学校读者我要写书评

暂无评论

Coscheduled distributed-web servers on system area network

引用

JOURNAL OF PARALLEL AND DISTRIBUTED COMPUTING 2008年第8期68卷 1033-1043页

作者： Kim, Jin-Ha Choi, Gyu Sang Das, Chita R. Penn State Univ Dept Comp Sci & Engn University Pk PA 16802 USA

As cluster-based web servers are increasingly adopted to host a variety of network-based services, improving the performance of such servers has become critical to satisfy the customers' demands. Especially, the user response time is an important factor so that clients feel satisfied with the web services. In this paper, we investigate the feasibility of minimizing the response time of a server by exploiting the advantages of both user-level communication and coscheduling. We, thus, propose a coscheduled server model based on the recently proposed distributed PRESS web server, where the remote cache accesses can be coscheduled on different nodes to reduce the response time. We experiment this concept using two known coscheduling techniques, called dynamic coscheduling (DCS) and DCS with immediate blocking. We have developed a comprehensive simulation testbed that captures the underlying communication layer in a cluster, the characteristics of various coscheduling algorithms, and the characteristics of the distributed server model to estimate the average delay and throughput with different system configurations. The accuracy of the VIA communication layer and the DCS mechanism is verified using measurements on a 16-node Linux cluster. Extensive simulation of four server models (PRESS over VIA, coscheduled PRESS model with DCS, with DCS and blocking, and Adaptive) using 32-node cluster configurations indicates that the average response time of a distributed server can be minimized significantly by coscheduling the communicating processes. The use of the DCS scheme reduced the average latency up to four times to the PRESS over VIA model that uses only user-level communication. (C) 2008 Published by Elsevier Inc.

关键词： cluster-based web server coscheduling user-level communication webswitch Pareto distribution

来源：评论

学校读者我要写书评

暂无评论

CTFS: A new light-weight, cooperative temporary file system for cluster-based web servers

CTFS: A new light-weight, cooperative temporary file system ...

引用

IEEE International Conference on cluster Computing

作者： Wang, J Univ Nebraska Dept Comp Sci & Engn Lincoln NE 68588 USA

ISBN: (纸本)0769520669

Previous studies showed that I/O could become a major performance bottleneck in cluster-based web servers. Adopting a large I/O buffer cache on separate server nodes is not a good performance-cost scheme and sometime infeasible because of the high price and poor reliability Current native file systems do not work well for the poor performance. Specialized file systems suffer a poor portability problem. In this paper, we present a new light-weight, cooperative temporary, file system (called CTFS) to boost I/O performance for cluster-based web servers. CTFS has the following advantages: (a) consists of a peer-to-peer cooperative caching system using user-level communication technique to eliminate repeated file requests and conduct aggressive remote prefetch, (b) runs in the user space to achieve a good portability,, (c) organizes a group of files with good associated access locality together to form a cluster unit on disk and thereby providing a sustained high I/O performance without degradation. Comprehensive trace-driven simulation experiments show that, CTFS achieves tip to a 37% better entire system throughput and reduces up to 47% total disk I/O latency than those in asynchronous FFS for a 64 node cluster-based web server.

关键词： temporal file system cooperative cluster-based web server disk I/Os performance improvement

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：