Grid VFS中代理管理客户端磁盘缓存的设计与实现

设计并实现了在网格虚拟文件系统Grid VFS客户端采用代理管理磁盘缓存来隐藏网络延迟，提高网格数据利用率。此方法扩展了虚拟化分布式文件系统，提高了对网格资源有效完整的数据访问。在Grid VFS中，客户端代理动态地产生和管理磁盘缓存，每一个未修改的应用程序和OS都能应用，支持write-back策略、文件系统之间缓存的共享以及磁盘缓存的多级化，通过用户级VFS可以完整的集成到网格应用程序和资源中，从而提高了网格数据的访问性能。     

局域存储网格设计与实现

研究局部范围内存储资源的有效共享问题,设计了一个实用的局域存储网格系统,并就该系统的体系结构、元数据管理、存储资源分配策略、文件传输服务等问题做了较深入的讨论.该系统具有透明性、高效性,实时性,屏蔽了存储资源的分布性,异构性等特征,为用户提供了快速、方便的存储资源使用环境,同时也提高了存储资源的利用率.     

云计算整合计算资源

云计算对于服务器资源、存储资源进行了统一管理,而后根据应用需求的多少动态地对这些资源进行调整。相对于网格技术,它更为切合互联网企业的需求,目前Google、Amazon等用户已经开始尝到云计算的甜头。     

Griddaen数据网格系统的设计与关键技术实现

科学计算领域中的科学数据呈现爆炸式增长，未来的科学计算将以数据为中心，数据网格计算技术成为解决复杂海量科学数据的访问和管理的一种有效技术。设计和实现的Gfiddaen数据网格系统，可以管理多个分布异构的存储资源的数据，为用户提供统一的数据访问。重点介绍了数据网格系统体系结构，以及系统的设计原则和目标，并讨论了系统主要关键技术的实现。     

语义网格核心技术及其应用研究

网格是近年来兴起的一个研究热点。它旨在使互联网上所有资源(计算资源、存储资源、通信资源、软件资源、信息资源、知识资源等)实现全面共享与协同工作,使整个因特网整合成一台巨大的超级计算机,为用户提供"即连即用"式的服务。语义网格结合了网格,语义网和Web服务的优点。本文介绍了网格和语义网格的概念,讨论了语义网格的框架,分析了语义网格的核心技术;介绍了语义网格的应用,并对语义网格发展面临的困难及其未来的前景进行了分析探讨。     

语义网格核心技术及其应用研究

网格是近年来兴起的一个研究热点。它旨在使互联网上所有资源(计算资源、存储资源、通信资源、软件资源、信息资源、知识资源等)实现全面共享与协同工作,使整个因特网整合成一台巨大的超级计算机,为用户提供"即连即用"式的服务。语义网格结合了网格,语义网和Web服务的优点。通过讨论语义网格的框架,分析了语义网格的核心技术;研究了语义网格的应用,并对语义网格发展面临的困难及其未来的前景进行了分析探讨。     

基于网格环境的GOS网格文件系统的研究

基于网格环境的GOS文件系统与一般计算机文件系统有很大区别。文章给出网格文件系统的体系结构,引入路径解析机制、Mount机制、文件访问控制机制等,对网格文件系统的设计进行了研究。     

网格技术与信息资源存储和共享

“网格“是一个新出现的概念,代表了一种先进的技术和基础设施,是继Internet之后又一次重大的科技进步.网格旨在使互联网上所有资源(计算资源、存储资源、通信资源、软件资源、信息资源、知识资源等)实现全面共享与协同工作,使整个因特网整合成一台巨大的超级计算机,为用户提供“即连即用“式的服务.介绍了网格的内涵、特点及两种主要的网格体系结构,对网格环境下信息资源的存储和共享进行了论述.     

数据网格及其关键技术研究

从应用需求出发，首先分析了探讨了数据网格的基本目标：命名的透明性、定位的透明性、协议的透明性和时间的透明性，以及数据网格提供的基本服务：目录服务、注册与发布、信息发现、存储资源代理服务、身份认证与访问控制、调度和方法执行等，深入研究了数据网格的关键技术-元数据目录和存储资源代理，最后介绍了一个海量信息处理系统的设计。     

网格环境下数据副本创建策略

本文在网格环境中探讨了数据副本创建策略,包括域内副本衍生和域间副本扩展策略。策略选择恰当的时机和地点创建副本,在充分利用存储资源的同时改善了用户的访问速度和带宽消耗。     

校园网格文件系统的研究

随着信息技术的发展,科学计算和并行技术所要处理的数据越来越多,现有的分布式文件系统已经越来越难以满足海量数据存储和资源在地理上的广泛协同和共享。校园网格文件系统是解决建立校园网格系统的重要技术之一,它将校园网格系统中的资源有机地统一起来,其应用将促进网格研究的进一步发展。     

Internet资源库——面向主题的数据网格模型

提出的Internet资源库体系结构,是一种面向主题的数据网格模式,使Internet上各数据源可以动态地上推自己的数据,作为其他数据源的子模式;支持多数据库的单一化访问,屏蔽多数据库的数据结构,为客户提供一致、规范的数据外貌。     

An Anticipative Recursively Adjusting Mechanism for parallel file transfer in data grids

Data Grids enable the sharing, selection, and connection of a wide variety of geographically distributed computational and storage resources for content needed by large‐scale data‐intensive applications such as high‐energy physics, bioinformatics, and virtual astrophysical observatories. In Data Grids, co‐allocation architectures were developed to enable parallel downloads of data sets from selected replica servers. As Internet is usually the underlying network of a grid, network bandwidth plays as the main factor affecting file transfers between clients and servers. In this paradigm, there are still some challenges that need to be solved, such as to reduce differences in finish times between selected replica servers, to avoid traffic congestion resulting from transferring the same blocks in different links among servers and clients, and to manage network performance variations among parallel transfers. In this paper, we propose the Anticipative Recursively Adjusting Mechanism (ARAM) scheme to adjust the workloads on selected replica servers and handle unpredictable variations in network performance by those servers. Our algorithm is based on using the finish rates for previously assigned transfers to anticipate the bandwidth status for the next section to adjust workloads, and to reduce file transfer times in grid environments. Our approach is useful in grid environments with unstable network link. It not only reduces idle time wasted waiting for the slowest server, but also decreases file transfer completion times. Copyright © 2010 John Wiley & Sons, Ltd.     

高能物理网格数据管理关键技术研究*

首先概要介绍高能物理网格的需求和发展,然后对其中数据管理的关键技术进行深入分析和探讨,包括名字服务、数据复制管理、数据传输、海量存储系统、用户访问接口等.最后,介绍一个用于高能物理网格数据管理的文件系统原型设计.     

Enhanced Dynamic Hierarchical Replication and Weighted Scheduling Strategy in Data Grid

The Data Grid provides massive aggregated computing resources and distributed storage space to deal with data-intensive applications. Due to the limitation of available resources in the grid as well as production of large volumes of data, efficient use of the Grid resources becomes an important challenge. Data replication is a key optimization technique for reducing access latency and managing large data by storing data in a wise manner. Effective scheduling in the Grid can reduce the amount of data transferred among nodes by submitting a job to a node where most of the requested data files are available. In this paper two strategies are proposed, first a novel job scheduling strategy called Weighted Scheduling Strategy (WSS) that uses hierarchical scheduling to reduce the search time for an appropriate computing node. It considers the number of jobs waiting in a queue, the location of the required data for the job and the computing capacity of the sites Second, a dynamic data replication strategy, called Enhanced Dynamic Hierarchical Replication (EDHR) that improves file access time. This strategy is an enhanced version of the Dynamic Hierarchical Replication strategy. It uses an economic model for file deletion when there is not enough space for the replica. The economic model is based on the future value of a data file. Best replica placement plays an important role for obtaining maximum benefit from replication as well as reducing storage cost and mean job execution time. So, it is considered in this paper. The proposed strategies are implemented by OptorSim, the European Data Grid simulator. Experiment results show that the proposed strategies achieve better performance by minimizing the data access time and avoiding unnecessary replication.     

可扩展网格文件访问接口的设计与实现

描述了网格文件访问接口(GFAI)的设计和实现。GFAI实现了一个与POSIX标准兼容的、可扩展的网格文件访问接口，屏蔽了不同存储系统访问协议的细节，解决了不同网格文件访问/传输协议的异构性问题，为用户提供了一个统一的、易于使用的网格I/O接口。     

PDDRA: A new pre-fetching based dynamic data replication algorithm in data grids

In recent years, grid technology has had such a fast growth that it has been used in many scientific experiments and research centers. A large number of storage elements and computational resources are combined to generate a grid which gives us shared access to extra computing power. In particular, data grid deals with data intensive applications and provides intensive resources across widely distributed communities. Data replication is an efficient way for distributing replicas among the data grids, making it possible to access similar data in different locations of the data grid. Replication reduces data access time and improves the performance of the system. In this paper, we propose a new dynamic data replication algorithm named PDDRA that optimizes the traditional algorithms. Our proposed algorithm is based on an assumption: members in a VO (Virtual Organization) have similar interests in files. Based on this assumption and also file access history, PDDRA predicts future needs of grid sites and pre-fetches a sequence of files to the requester grid site, so the next time that this site needs a file, it will be locally available. This will considerably reduce access latency, response time and bandwidth consumption. PDDRA consists of three phases: storing file access patterns, requesting a file and performing replication and pre-fetching and replacement. The algorithm was tested using a grid simulator, OptorSim developed by European Data Grid projects. The simulation results show that our proposed algorithm has better performance in comparison with other algorithms in terms of job execution time, effective network usage, total number of replications, hit ratio and percentage of storage filled.     

ERFT：一种增强型的可靠文件传输工具

网格数据传输组件RFT提供了可靠文件传输服务,但是GT4中的RFT仍存在不支持xml配置文件、不能进行全局优化配置、不能可视化操作等不足。在研究GT4 RFT组件的基础上,设计和实现了一个增强型的可视化可靠文件传输工具——ERFT。对大型文件的传输实验表明,ERFT继承了RFT的传统优势,同时又改进了其不足,为用户提供了更为可靠、友好的文件传输服务。     

基于OGSA标准的发票数据库网格IDBGrid的设计与实现

该文根据OGSA标准提出将分布于全国各地的成千发票数据库虚拟化,通过对原系统的重新规划与设计,建成一个具有超强的存储和运算能力的发票数据库网格IDBGrid,IDBGrid在Web服务资源框架基础上提供网格数据库管理系统注册服务、网格数据库管理服务、网格数据服务、网格数据库复制服务、网格数据库监控服务、网格数据库故障转移服务等,提供一个统一、透明的数据库网格访问和整合界面,通过网格环境下数据库服务器之间的协同处理达到提高资源利用率、运行性能,降低开发和维护成本,增强系统健壮性和可用性的目的,文章重点研究了异构环境下数据库管理系统的网格化管理的关键技术。