Using transparent files in a fault tolerant distributed file system

The peer-to-peer model and the bandwidth availability are fostering the creation of new distributed file systems. However, files belonging to local application and distributed applications are usually handled in the same way by the local file system, so both contribute equally to consume storage space. This paper presents a peer-to-peer distributed file system which uses the “transparent file” concept to improve its fault tolerance and file availability. Files are kept as transparent/volatile replicas, using the free space available in each local file system. When a replica is invalidated, peers cooperate to restore it. The proposed architecture was implemented and tested; experiments showed its feasilibity, and that its costs are proportional to the size of files being replicated. The occurrence of multiple simultaneous replica invalidations did not impose a significant overhead.