Distributed File Systems
In the previous chapter, we discussed network construction and the low-level protocols needed to transfer messages between systems. Now we examine one use of this infrastructure. A distributed file system (DFS) is a distributed implementation of the classical time-sharing model of a file system, where multiple users share files and storage resources (Chapter 11). The purpose of a DFS is to support the same kind of sharing when the files are physically dispersed among the sites of a distributed system.
In this chapter, we describe how a DFS can be designed and implemented. First, we discuss common concepts on which DFSs are based. Then, we illustrate our concepts by examining one influential DFS—the Andrew file system (AFS).
• To explain the naming mechanism that provides location transparency and independence.
• To describe the various methods for accessing distributed files.
• To contrast stateful and stateless distributed file servers.
• To show how replication of files on different machines in a distributed file system is a useful redundancy for improving availability.
• To introduce the Andrew file system (AFS) as an example of a distributed file system.
As we noted in the preceding chapter, a distributed ...