不同MapReduce运行系统的性能测试与分析

随着云计算技术的发展,许多MapReduce运行系统被开发出来,如Hadoop、Phoenix和Twister等.直观上,Hadoop具有很强的可扩展性、稳定性,适合处理大规模离线应用;Phoenix具有运行速度快等优点,适合处理数据密集型任务;Twister是轻量级的迭代系统,非常适合迭代式的应用.不同的应用在不同的MapReduce运行系统中有着不同的性能.通过测试不同应用在这些运行系统上的性能,给出了实验比较和性能分析,从而为大数据处理时选择合适的并行编程模型提供依据.     

Hadoop云平台MapReduce模型优化研究

针对Hadoop平台MapReduce分布式计算模型运行机制中的顺序制约而产生的计算资源浪费问题,从提高平台中每个执行节点的细粒度并行数据处理角度出发,结合Java共享内存多线程编程技术,对该模型进行了优化,提出一种MapReduce+OpenMP粗细粒度相结合的分布式并行计算模型。并在由四个节点组成的Hadoop集群环境下对不同规模大小的出租车GPS轨迹数据分析处理,验证该模型的性能和效率,实验结果证明MapReduce+OpenMP分布式并行计算模型确实能够提高针对大数据集的计算效率,是对Hadoop平台大数据分析处理模型有效的完善和优化。     

基于最小生成树的大规模数据分类模型及其MapReduce实现

数据的快速增长,为我们提供了更多的信息,然而,也对传统信息获取技术提出了挑战。这篇论文提出了MCMM算法,它是基于MapReduce的大规模数据分类模型的最小生成树（MST）的算法。它可以看做是介于传统的KNN方法和基于聚类分类方法之间的模型,旨在克服这两种方法的不足并能处理大规模的数据。在这一模型中,训练集作为有权重的无向完全图来处理。顶点是对象,两点之间边的权重是对象间的距离。这一距离,不同于欧几里得距离,它是一个特定的距离度量。这样,可以找到图中最小生成树集,其中,图中每棵树代表一个类。为了降低时间复杂度,提取了每棵树中最具代表性的点来代表该树。这些压缩了的点集,可以通过计算无标签对象和它们之间的距离,来进行分类。MCMM模型基于MapReduce实现并且部署在Hadoop平台。该模型可扩展处理大规模的数据,是因为Hadoop支持数据密集分布应用,并且这些应用可以和数以千计的节点和数据一起运作。另外,MapReduce 和Hadoop能在由商品机组成的集群上很好的运行。MCMM模型使用云平台并且通过使用MapReduce 和Hadoop进行云计算是有益处的。实验采用的数据集包括从UCI数据库得到的真实数据和一些模拟数据,实验使用了4000个集群。实验表明,MCMM模型在精确度和扩展性上优于KNN和其他一些经常使用的基础分类方法。     

Extending Science Gateway Frameworks to Support Big Data Applications in the Cloud

Cloud computing offers massive scalability and elasticity required by many scientific and commercial applications. Combining the computational and data handling capabilities of clouds with parallel processing also has the potential to tackle Big Data problems efficiently. Science gateway frameworks and workflow systems enable application developers to implement complex applications and make these available for end-users via simple graphical user interfaces. The integration of such frameworks with Big Data processing tools on the cloud opens new opportunities for application developers. This paper investigates how workflow systems and science gateways can be extended with Big Data processing capabilities. A generic approach based on infrastructure aware workflows is suggested and a proof of concept is implemented based on the WS-PGRADE/gUSE science gateway framework and its integration with the Hadoop parallel data processing solution based on the MapReduce paradigm in the cloud. The provided analysis demonstrates that the methods described to integrate Big Data processing with workflows and science gateways work well in different cloud infrastructures and application scenarios, and can be used to create massively parallel applications for scientific analysis of Big Data.     

Copernicus,a hybrid dataflow and peer-to-peer scientific computing platform for efficient large-scale ensemble sampling

Compute-intensive applications have gradually changed focus from massively parallel supercomputers to capacity as a resource obtained on-demand. This is particularly true for the large-scale adoption of cloud computing and MapReduce in industry, while it has been difficult for traditional high-performance computing (HPC) usage in scientific and engineering computing to exploit this type of resources. However, with the strong trend of increasing parallelism rather than faster processors, a growing number of applications target parallelism already on the algorithm level with loosely coupled approaches based on sampling and ensembles. While these cannot trivially be formulated as MapReduce, they are highly amenable to throughput computing. There are many general and powerful frameworks, but in particular for sampling-based algorithms in scientific computing there are some clear advantages from having a platform and scheduler that are highly aware of the underlying physical problem. Here, we present how these challenges are addressed with combinations of dataflow programming, peer-to-peer techniques and peer-to-peer networks in the Copernicus platform. This allows automation of sampling-focused workflows, task generation, dependency tracking, and not least distributing these to a diverse set of compute resources ranging from supercomputers to clouds and distributed computing (across firewalls and fragile networks). Workflows are defined from modules using existing programs, which makes them reusable without programming requirements. The system achieves resiliency by handling node failures transparently with minimal loss of computing time due to checkpointing, and a single server can manage hundreds of thousands of cores e.g. for computational chemistry applications.     

云计算环境下关联规则挖掘算法的研究

云计算为存储和分析海量数据提供了廉价高效的解决方案,云计算环境下的数据挖掘算法的研究具有重要的理论意义和应用价值。针对云计算环境下的关联规则挖掘算法展开研究,介绍了云计算的概念、Hadoop框架平台、MapReduce编程模型和传统的Apriori算法;在此基础上,以实现云计算环境下的并行化数据挖掘为目的,对Apriori算法进行了改进,给出了改进的算法在Hadoop中的MapReduce编程模型上的执行流程;通过一个简单的频繁项集挖掘实例展示了改进的算法的执行效率及实用性。     

iMapReduce: A Distributed Computing Framework for Iterative Computation

Iterative computation is pervasive in many applications such as data mining, web ranking, graph analysis, online social network analysis, and so on. These iterative applications typically involve massive data sets containing millions or billions of data records. This poses demand of distributed computing frameworks for processing massive data sets on a cluster of machines. MapReduce is an example of such a framework. However, MapReduce lacks built-in support for iterative process that requires to parse data sets iteratively. Besides specifying MapReduce jobs, users have to write a driver program that submits a series of jobs and performs convergence testing at the client. This paper presents iMapReduce, a distributed framework that supports iterative processing. iMapReduce allows users to specify the iterative computation with the separated map and reduce functions, and provides the support of automatic iterative processing within a single job. More importantly, iMapReduce significantly improves the performance of iterative implementations by (1) reducing the overhead of creating new MapReduce jobs repeatedly, (2) eliminating the shuffling of static data, and (3) allowing asynchronous execution of map tasks. We implement an iMapReduce prototype based on Apache Hadoop, and show that iMapReduce can achieve up to 5 times speedup over Hadoop for implementing iterative algorithms.     

SparkDE:一种基于RDD云计算模型的并行差分进化算法

云计算MapReduce并行编程模型广泛应用于数据密集型应用领域,基于该模型的开源平台Hadoop在大数据领域获得了成功应用。然而,对于计算密集型任务,特别是迭代运算,频繁启动Map和Reduce过程将导致负载过大,影响计算效率。弹性分布式数据集(RDD)是一种基于内存的集群计算模型,有效地支持迭代运算,能够克服负载过大的问题。因此提出基于RDD模型的并行差分进化算法SparkDE。SparkDE首先将整个种群划分为若干个独立岛,然后将一个岛对应RDD中的一个分区,每个岛在RDD的一个分区中独立进化指定代数后,利用迁移算子在岛之间交换信息。利用标准测试问题对SparkDE、基于MapReduce模型的MRDE和基本DE进行对比实验研究。实验结果表明SparkDE求解精度高,计算速度快,加速效果明显,可以作为云计算平台的下一代优化器。     

Cloud computing paradigms for pleasingly parallel biomedical applications

Cloud computing offers exciting new approaches for scientific computing that leverage major commercial players’ hardware and software investments in large‐scale data centers. Loosely coupled problems are very important in many scientific fields, and with the ongoing move towards data‐intensive computing, they are on the rise. There exist several different approaches to leveraging clouds and cloud‐oriented data processing frameworks to perform pleasingly parallel (also called embarrassingly parallel) computations. In this paper, we present three pleasingly parallel biomedical applications: (i) assembly of genome fragments; (ii) sequence alignment and similarity search; and (iii) dimension reduction in the analysis of chemical structures, which are implemented utilizing a cloud infrastructure service‐based utility computing models of Amazon Web Services ( http://Amazon.com Inc., Seattle, WA, USA) and Microsoft Windows Azure (Microsoft Corp., Redmond, WA, USA) as well as utilizing MapReduce‐based data processing frameworks Apache Hadoop (Apache Software Foundation, Los Angeles, CA, USA) and Microsoft DryadLINQ. We review and compare each of these frameworks, performing a comparative study among them based on performance, cost, and usability. High latency, eventually consistent cloud infrastructure service‐based frameworks that rely on off‐the‐node cloud storage were able to exhibit performance efficiencies and scalability comparable to the MapReduce‐based frameworks with local disk‐based storage for the applications considered. In this paper, we also analyze variations in cost among the different platform choices (e.g., Elastic Compute Cloud instance types), highlighting the importance of selecting an appropriate platform based on the nature of the computation. Copyright © 2011 John Wiley & Sons, Ltd.     

基于Hadoop的贝叶斯过滤MapReduce模型

传统分布式大型邮件系统对海量邮件的过滤存在编程难、效率低、前期训练耗用资源大等缺点,为此,对传统贝叶斯过滤算法进行并行化改进,利用云计算MapReduce模型在海量数据处理方面的优势,设计一种基于Hadoop开源云架构的贝叶斯邮件过滤MapReduce模型,优化邮件的训练和过滤过程。实验结果表明,与传统分布式计算模型相比,该模型在召回率、查准率和精确率方面性能较好,同时可降低邮件过滤成本,提高系统执行效率。     

MRA++: Scheduling and data placement on MapReduce for heterogeneous environments

MapReduce has emerged as a popular programming model in the field of data-intensive computing. This is due to its simplistic design, which provides ease of use for programmers, and its framework implementations such as Hadoop, which have been adopted by large business and technology companies. In this paper we make some improvements to the Hadoop MapReduce framework by introducing algorithms that are suitable for heterogeneous environments. The goal is to efficiently perform data-intensive computing in heterogeneous environments. The need for these adaptations derives from the fact that, following the framework design proposed by Google, Hadoop is optimized to run in large homogeneous clusters. Hence we propose MRA++, a new MapReduce framework design that considers the heterogeneity of nodes during data distribution, task scheduling and job control. MRA++establishes a training task to gather information prior to the data distribution. However, we show that the delay introduced in the setup phase is offset by the effectiveness of the mechanisms and algorithms, that achieve performance gains of more than 70% in 10 Mbps networks.     

Flame-MR: An event-driven architecture for MapReduce applications

Nowadays, many organizations analyze their data with the MapReduce paradigm, most of them using the popular Apache Hadoop framework. As the data size managed by MapReduce applications is steadily increasing, the need for improving the Hadoop performance also grows. Existing modifications of Hadoop (e.g., Mellanox Unstructured Data Accelerator) attempt to improve performance by changing some of its underlying subsystems. However, they are not always capable to cope with all its performance bottlenecks or they hinder its portability. Furthermore, new frameworks like Apache Spark or DataMPI can achieve good performance improvements, but they do not keep compatibility with existing MapReduce applications. This paper proposes Flame-MR, a new event-driven MapReduce architecture that increases Hadoop performance by avoiding memory copies and pipelining data movements, without modifying the source code of the applications. The performance evaluation on two representative systems (an HPC cluster and a public cloud platform) has shown experimental evidence of significant performance increases, reducing the execution time by up to 54% on the Amazon EC2 cloud.     

基于MapReduce的关联规则增量更新算法

云计算以其强大的存储和计算能力而成为解决海量数据挖掘问题的有效途径。经典的关联规则增量更新算法FUP需要频繁扫描原数据集,不适用于海量数据的处理。文中以提高海量数据上关联规则增量更新效率为目标,将FUP算法与云计算的MapReduce编程模式相结合,提出了一种基于MapReduce的关联规则增量更新算法MRFUP。该算法只需扫描原数据集一次,并能充分利用云计算强大的存储和并行计算能力。基于Hadoop的实验结果表明,MRFUP算法可提高对海量数据的处理能力和效率,适用于海量数据的关联规则挖掘。     

基于匹配规则的MapReduce任务调度模型

基于开源云计算平台Hadoop的MapReduce是当前流行的分布式计算框架之一,然而其先进先出(FIFO)调度算法存在资源利用效率低下的问题。提出了一种基于资源匹配规则的MapReduce任务调度模型并进行了算法实现。该调度模型通过获取任务的资源需求与计算节点的剩余资源,依据资源的匹配性进行任务分配,提高了系统的资源使用效率。首先对MapReduce的调度过程进行建模,提出了资源及匹配度的量化定义和相应的计算公式;然后给出了资源测量的具体方法及算法实现;最后利用TeraSort、GrepCount和WordCount任务与FIFO调度算法进行实验对比,实验结果显示,最好的情况下,提出的调度模型任务完成时间减少了22.19%,而最差情况下的吞吐量也提高了25.39%。     

基于Hadoop的高性能海量数据处理平台研究

海量数据高性能计算蕴藏着巨大的应用价值,但是目前云计算体系只具有海量数据处理能力,而不具有足够的高性能计算能力。将具有超强并行计算能力的CPU与云计算相融合,提出了基于CPU/GPU协同的异构高性能云计算体系结构。以开源Hadoop为基础,采用注释码的形式对MapReduce函数中需要并行的部分进行标记。通过 定制GPU类加载器,将被标记代码转换为CUDA代码并动态编译运行。该平台将GPU的计算能力融合到MapReduce框架中,可高效处理海量数据。     

云计算下的SPRINT并行算法研究

目前,由于云计算的出现,越来越多的中小企业在分析海量数据时能便利地找到廉价的解决方案。本文,鉴于MapReduce作为Hadoopd中的重要编程模型,在介绍基于云计算的Hadoop平台和数据挖掘技术中的SPRINT分类算法的基础上,详细描述SPRINT的并行算法在MapReduce编程模型上的执行流程,并利用研究出的决策树模型对输入数据进行分类。     

Hadoop平台在云计算中的应用

云计算是当前比较热门的新兴技术之一,受到业界的广泛关注。Hadoop是一个可实现大规模分布式计算的开源软件平台,因此被广泛应用在云计算领域。本文在对Hadoop的主要组件Hadoop分布式文件系统HDFS（Hadoop Distributed File System）和计算模型MapReduce进行深入分析和研究的基础上,建立基于Hadoop平台的云计算模型,通过实验证明该模型可以有效完成分布式数据处理任务。     

基于决策树挖掘算法的气象大数据云平台设计

大数据、云计算技术的迅猛发展为挖掘气象数据丰富的科研和经济价值提供了技术支撑,促进了Hadoop及其包含的文件存储系统(HDFS,Hadoop Distributed File System)和分布式计算模型在气象数据处理领域广泛应用。由于气象数据具有大数据的4V特征,还需要引入新的数据处理算法来提高气象数据处理效率。通过对决策树算法原理的研究,基于Hadoop云平台,创建随机森林模型,为数据挖掘算法在云平台上的应用提供一种新的可能性。基于决策树(CART,Classification And Regression Trees)挖掘算法的气象大数据云平台设计,采用Hadoop系统架构和MapReduce工作流程,对气象大数据云平台采用集群部署。平台总体架构分为基础设施层、数据管理与处理层、应用层,减少了决策树建立的时间,实现了气象数据高效加工和挖掘分析等平台功能。     

云计算中Hadoop技术研究与应用综述

Hadoop作为当今云计算与大数据时代背景下最热门的技术之一,其相关生态圈与Spark技术的结合一同影响着学术发展和商业模式。首先介绍了Hadoop的起源和优势,阐明相关技术原理,如MapReduce,HDFS,YARN,Spark等;然后着重分析了当前Hadoop学术研究成果,从MapReduce算法的改进与创新、HDFS技术的优化与创新、二次开发与其它技术相结合、应用领域创新与实践4个方面进行总结,并简述了国内外应用现状。而Hadoop与Spark结合是未来的趋势,最后展望了Hadoop未来研究的发展方向和亟需解决的问题。