一种策略灵活的多版本文件系统的设计与实现

设计并实现了一种新型的多版本文件系统——HFS。HFS把启发式规则和用户规则结合起来，提供灵活的版本保留策略，为必要的文件保留必要的版本，节省了存储空间。同时，还通过写时复制和目录版本等技术，进一步降低对存储资源的消耗。分析表明，该系统可以在保证数据可靠性的同时，有效地提高存储资源的利用率。HFS的实现基于Ext3，对HFS和Ext3的文件读写性能的测试和比较的结果表明，HFS的顺序读文件的性能与Ext3相当，顺序写文件的性能和随机读写的性能比Ext3降低了2％-5％，版本机制对文件系统性能的影响很小。

Design and implementation of a versioning file system with flexible retention policy

This paper proposes a new prototype of versioning file system,named Hao's file system (HFS).The system com- bines the heuristic rule with the user rule to establish a flexible retention policy,keeping necessary versions for necessary files and reducing space consumption.Furthermore,it makes good use of storage resource through the copy-on-writing technology and the directory versioning mechanism.The analysis showed that the HFS could enhance storage efficiency effectively while providing guaranteed data rel...