【作者】 刘丹；

【导师】 刘心松；

【作者基本信息】 电子科技大学 ， 计算机应用技术， 2005， 博士

【摘要】 以现有的网络及分布式技术为基础，研究广域网尺度的文件资源共享和重用，针对性地提出了虚拟网络文件系统(VIRTUAL NETWORK FILE SYSTEM---VNFS)模型。VNFS统一化管理广域网络上的各类文件资源，为用户提供统一的共享文件系统。 论文围绕实现VNFS的关键技术问题，包括系统逻辑结构组织、文件全局名字空间服务、副本管理技术、数据一致性技术等展开研究讨论，提出了若干新算法和方法，并进行了相关的原型系统设计和算法性能试验。 第一章论述了VNFS系统研究的必要性和应用环境。第二章对目前已有研究综述和分析，讨论了目前网络共享文件系统的现状及存在的问题，明确了研究的主要内容。第三章给出本文研究的内容，包括设计一个灵活的、能够逼近于物理网络拓扑的逻辑组织结构；实现VNFS的全局名字空间GNS(Global Name Space)；高效的副本管理机制及数据一致性维护机制。 VNFS结构原型及模块功能描述在第四章中展开，整个VNFS系统按照完全对等的思想设计，任何一个加入VNFS系统的服务节点都安装VNFS功能软件并可以充当其中的任何角色。第五章详细描述了VNFS的逻辑组织构建方法---一个自组织叠加网模型的设计及相应的算法实现，并从理论上证明了其高效性。第六章以自组织算法为基础构建了VNFS的全局名字空间，提出了分别从物理特征、逻辑特征、用户使用特征三个层次对文件命名的方法，并建立三个层次文件名字间的映射关系，提高了名字解析效率。 第七章给出VNFS的副本管理方法，其针对广域网特征进行了新的设计。提出了适应于局域网和广域网环境的两个副本管理算法，并证明了算法在提高文件访问服务质量方面的良好性能。第八章给出应用于VNFS系统中的一种动态数据同步方法以及一个分布式互斥锁算法。该动态数据同步方法综合了扩散机制和失效机制的特点，提高了同步效率；该分布式互斥算法基于请求的读写特征设计，降低了系统分布式互斥的通信开销。更多还原

【Abstract】 Based on the network and distributed technology, a model named virtual network file system(VNFS),which unites all the physical file systems into one virtual network file system to the users, is presented to research the ways of sharing and reusing the files on the wide area.The key problems in VNFS, such as system architecture, global name space, replication management and data consistency etc. will be discussed in this thesis. Some new algorithms and ideas, whose performances are analyzed and original modal is designed, will also be presented.In chapter one, I explain why we need to research VNFS and what the application environment is. In chapter two, I further analyze and summarize the actualities and disadvantage of the network file system and determine the key problems of research. In chapter three, the main research contents are described, including: designing a logical architecture which is flexible and approachable to physical network, completing GNS(Global Name Space) of VNFS, implementing a high-efficient replication management algorithms and data coherence algorithms.In chapter four, the architecture model of VNFS and the functions of every module are described. The VNFS is designed as the peer-to-peer model and every site in VNFS can play any role. In chapter five, a hierachical self-organizing overlay network model based on clustering, which is the base of VNFS logical organization, is proposed and the efficiency of this model is proved theoretically. In chapter six, the GNS of VNFS is designed based on the self-organizing overlay network model. A three layers name space, which are physical layer, logical layer and application layer, is proposed, and the relations among the three layers are presented. Using this name space we can accelerate the process of looking up a file.In chapter seven, the methods of VNFS replication management are presented, which are based on the replication management methods in distributed file systems and expand some new characteristics to fit the WAN environments. Two replication更多还原