一种块级别多模式数据容灾模型

提出一种基于Linux平台逻辑卷管理系统的块级别多模式数据容灾模型,论述了其系统结构与工作流程,并详细讨论了快照数据备份、连续数据保护、远程数据复制3种容灾模式的工作原理与关键技术。     

一种单向数据复制的实现方法

文章主要介绍了单向数据复制的方法.作者根据工作中的实际经验,提出了数据复制的一种方案.     

基于层次结构的远程数据复制系统

针对传统的集中式复制结构存在的单点瓶颈和扩展性差等不足，提出了基于层次化结构的数据复制系统。通过将复制节点之间的拓扑结构抽象为图，提出了使用最小代价树的方式对节点进行组织。通过将数据由树根逐层扩散复制到树叶，使得在保证数据一致性的同时，分散了主节点的负荷。最后分析了使用复制数据进行灾难恢复的过程，并通过原型实验对集中式与层次化复制结构进行了比较。     

一种新的集群Web服务器体系结构及其数据复制算法

数据副本管理是集群Web服务器(CWS)的一个重要研究内容，它与CWS的体系结构和具体的应用密不可分。文章提出了一种架构于IJnux虚拟服务器(INS)基础之上、应用广泛、可扩展性强的集群Web服务器结构，给出了相应特定的数据复制算法，包括数据定位和数据同步。通过实验对此复制算法进行了测试与分析，并和其它复制方案进行了比较，证明了本算法具有更高的可用性和更好的性能。     

分布式系统数据复制的研究

在分布式系统中,由于复制能够增强性能,提供高可用性和容错能力,因此它是保证分布式系统有效性的一个关键技术。为了保证数据安全、可用、可靠、可扩展性和服务的高效、连续性,分布式存储系统需要完善的数据管理机制。主要讨论数据复制的基本原则,用于复制数据管理的基本体系结构模型,副本对象上进行的一个操作通常涉及的5个阶段,以及在这个模型下不同的复制数据的方式是如何提供容错服务的,并在数据量大的情况下,对复制模型提出改进的方式。     

嵌入式移动数据库数据复制与同步研究

移动计算技术离不开嵌入式移动数据库的支持,嵌入式移动数据库系统的关键问题是数据复制与同步。介绍数据复制与同步的原理与机制,分析基于嵌入式移动数据库ASA的同步模型设计方案,最后阐述采用远程数据访问方法完成的Mobilink同步实现方案。     

一种单向数据复制的实现方法

文章主要介绍了单向数据复制的方法。作者根据工作中的实际经验，提出了数据复制的一种方案。     

SEPATON为全球数据密集型企业提供领先的远程复制解决方案

2009年5月26日,SEPATON公司发布了DeltaRemote软件,这是首个可供全球规模最大的数据密集型机构实现可靠且经济的远程数据复制产品。SEPATON新的DeltaRemote软件可以帮助企业用户更简便地进行大量数据的备份与复制，提供经济、高效的灾难保护。DeltaRemote的高性能、可扩展性和自动化性能，可满足大型企业对灾难恢复的需求，减少磁带处理的工作量,     

改善Client/Server系统性能的数据复制

在Ｃｌｉｅｎｔ／Ｓｅｒｖｅｒ体系结构中，性能关系系统实秀性的重要问题，合理的数据复制可以分散操作过程，提高系统对服务请响应速度，系统的可靠性和可用性，在开发实践的基础上，本文讨论了内／外存数据复制和主／辅数据复制的实现。     

移动数据库中数据复制同步处理策略分析

在实际的数据系统运行过程中,关联事务结果集会出现模型结合方面的问题,所以需要通过算法的更新来促进数据库的稳定运行。有关研究结果显示,数据库中的数据复制同步处理和常规的数据复制处理,有着实质性的区别,关联事务结果集模型会在信息化的基础上对移动事物进行优先处理,这样会有效的改善移动复制的结果,减少复制同步处理过程中存在的各种空间消耗问题。文章指出,更新算法在使用的过程中,会显著地提高数据处理和传输的效果,保证客户动态的可操控性。     

实现分布式数据库环境方法的研究与应用

深入探讨了在分布式数据库环境中如何维护多个副本的一致性,分析与比较了两种方法:分布式事务处理及数据复制,并在MicrosoftSQLServer系统下予以实现。     

分布式数据库系统及其一致性方法研究

分布式数据库系统是数据库领域中的一个主要研究方向,数据一致性维护是分布式数据库系统中的一个非常关键的技术问题。在分析分布式数据库系统体系结构的基础上,讨论了两种一致性方法:两阶段提交和复制服务器,并提出一种具有复制服务器的分布式数据库系统的结构框架,它具有有效性和实用性。     

提高嵌入式移动数据库数据可靠性的研究

随着移动技术的发展及智能移动终端的普及,人们对移动数据库实时处理和管理要求不断提高,嵌入式移动数据库越来越体现其优越性。主要阐述了嵌入式移动数据库的定义和特点,并对提高数据库的可靠性技术进行了研究,包括多线程技术,数据复制/缓存技术,数据的冲突检测机制。这对嵌入式移动数据库的发展具有重要意义并影响其未来的研究。     

Design of Enterprise Storage Architecture for Optimal Business Continuity

This paper presents a solution for optimal business continuity, with storage architecture for enterprise applications, which will ensure zero data loss and quick recovery. The solution makes use of Internet protocol storage area network （IPSAN）, which is used for data management without burdening the application server, as well as mix of synchronous and semi-synchronous replication techniques to replicate data to remote disaster recovery site. We have presented the detailed design of both synchronous and semi-synchronous with case study of using open source database postgres to prove our point for optimal business continuity. The theoretical presentation is also given for the same.     

Cost Based Data Dissemination in Satellite Networks

We consider the problem of data dissemination in a broadcast network. In contrast to previously studied models, broadcasting is among peers, rather than client server. Such a model represents, for example, satellite communication among widely distributed nodes, sensor networks, and mobile ad hoc networks. We introduce a cost model for data dissemination in peer to peer broadcast networks. The model quantifies the tradeoff between the inconsistency of the data, and its transmission cost; the transmission cost may be given in terms of dollars, energy, or bandwidth. Using the model we first determine the parameters for which eager (i.e. consistent) replication has a lower cost than lazy (i.e. inconsistent) replication. Then we introduce a lazy broadcast policy and compare it with several naive or traditional approaches to solving the problem.     

HLR Replication Protocols for Global Mobility Management in PCS Networks

The new trend for PCS networks is to provide mobile users with large-scalemobile capability across many service areas. In this scenario, global databasemanagement for PCS networks has become an increasingly important researchissue.In this paper, we examined two replicated database strategies,single-replica (SR) and multiple-replica (MR), for large-scalemobility of per-user data management in personal communicationnetworks. The SR strategy uses a single replica approach of HLR.The MR strategy replicates the per-user data of HLR in manyregions. The two strategies are based a partial replicationscheme, and a primary copy method is used to maintain replicas'consistency. Our numerical results show that the MR strategyoutperforms the SR strategy in most situations; however, it may beworse when the probability of a mobile user visiting a foreignregion is high and the query rates from other foreign regions arelow. Additionally, the number of replicas should be compact in theMR strategy in order to achieve a reasonable query response time.Therefore, we propose an adaptive multiple replication protocol tochoose a suitable replication strategy and to decide the optimizednumber of replicas.     

基于数据流的容灾技术的研究

提高分布式网络应用系统的容灾能力一直是近几年来人们关注的焦点。本文经过对现有容灾技术的讨论,又分析了分布式网络系统的数据交换过程,设计了一种基于数据流的通用容灾体系。提出了数据流复制以及数据流回放的容灾新理念,通过使用数据交互状态描述法以及增加灾备控制协议等关键技术,使容灾系统和正常业务系统的应用层工作分离开来,增强了系统的通用性和灵活性。并对该系统做了可行性分析,指出了该系统应用的前提条件。     

Minimizing data access latency in data grids by neighborhood‐based data replication and job scheduling

In Data Grid systems, quick data access is a challenging issue due to the high latency. The failure of requests is one of the most common matters in these systems that has an impact on performance and access delay. Job scheduling and data replication are two main techniques in reducing access latency. In this paper, we propose two new neighborhood‐based job scheduling strategies and a novel neighborhood‐based dynamic data replication algorithm (NDDR). The proposed algorithms reduce the access latency by considering a variety of practical parameters for decision making and the access delay by considering the failure probability of a node in job scheduling, replica selection, and replica placement. The proposed neighborhood concept in job scheduling includes all the nodes with low data transmission costs. Therefore, we can select the best computational node and reduce the search time by running a hierarchical and parallel search. NDDR reduces the access latency through selecting the best replica by performing a hierarchical search established based on the access time, storage queue workload, storage speed, and failure probability. NDDR improves the load balancing and data locality by selecting the best replication place considering the workload, temporal locality, geographical locality, and spatial locality. We evaluate our proposed algorithms by using Optorsim Simulator in two scenarios. The simulations confirm that the proposed algorithms improve the results compared with similar existing algorithms by 11%, 15%, 12%, and 10% in terms of mean job time, replication frequency, mean data access latency, and effective network usage, respectively.     

Cross-Layer Design for Data Accessibility in Mobile Ad Hoc Networks

Mobile ad hoc networks (MANET) are becoming an integral part of the ubiquitouscomputing and communication environment, providing new infrastructure formultimedia applications such as video phone, multimedia-on-demand, and others.In order to access multimedia information in MANET, Quality of Service (QoS)needs to be considered, such as high success rate to access multimedia data,bounded end-to-end delay, and others. In this paper, we present a dataaccessibility service for a group of mobile users to access desired data withhigh success rate. This accessibility service is only possible if we utilizeadvanced data advertising, lookup and replication services, as well as a novelpredictive location-based QoS routing protocol in an integrated fashion. Usingcross-layer design, we illustrate how the QoS routing protocol assists dataadvertising, lookup and replication services to achieve high data accesssuccess rate. Simulation results have shown that our design is successful ina dynamic MANET.