分布式文件系统低耦合度高可用性支持模块的实现

与现有的分布式文件系统的惯例——把数据高可用性的实现融合在文件系统中——不同，设计了一个数据高可用性子系统(data high availability module，DHAM)，用于为分布式文件系统提供数据高可用性支持．设计子系统的基本指导思想是把文件系统的高可用性实现从文件系统中抽取出来，作为一个单独的模块来实现，弱化它与文件系统其他部分之间的耦合性，使得二者之间仅仅有简单的接口关系．目的是使文件系统的设计更加模块化，并且便于对文件系统的容错这一主题进行专门的研究．DHAM已经成功地用于本研究所白行开发的分布式文件系统Clufs中，为其提供了数据高可用性支持．最后给出了模块的功能及性能测试结果，并对采用此模块前、后系统的出错概率进行了理论分析.

Implementation of a Weak Coupling and High Availability Module for a Distributed File System

A data high-availability subsystem-DHAM(data high availability module)-for a distributed file system is presented in this paper. It is different from the state-of-the-art schemes in which the data high availability implementation is embedded in the file system itself. The main idea is to extract the high availability implementation from the distributed file system and make it a separate module, and then keep simple interface between them. Two benefits are achieved from this scheme: the first, it makes the file system implementation more modular; the second, it is more convenient to make a special study of fault-tolerance of distributed file systems. DHAM has been successfully used in Clufs, a distributed file system implemented by the authors. Finally, the function and performance test results and the theoretical analysis are presented.