DISTRIBUTED SYSTEMS Principles and Paradigms Second Edition ANDREW S

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1 DISTRIBUTED SYSTEMS Principles and Paradigms Second Edition ANDREW S
DISTRIBUTED SYSTEMS Principles and Paradigms Second Edition ANDREW S. TANENBAUM MAARTEN VAN STEEN Chapter 11 DISTRIBUTED FILE SYSTEMS Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved

2 Client-Server Architectures (1)
Figure (a) The remote access model. (b) The upload/download model. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved

3 Client-Server Architectures (2)
Figure The basic NFS architecture for UNIX systems. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved

4 File System Model (1) Figure An incomplete list of file system operations supported by NFS. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved

5 File System Model (2) Figure An incomplete list of file system operations supported by NFS. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved

6 Cluster-Based Distributed File Systems (2)
Figure The organization of a Google cluster of servers. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved

7 Remote Procedure Calls in NFS
Figure (a) Reading data from a file in NFS version 3. (b) Reading data using a compound procedure in version 4. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved

8 Figure 11-11. Mounting (part of) a remote file system in NFS.
Naming in NFS (1) Figure Mounting (part of) a remote file system in NFS. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved

9 Naming in NFS (2) Figure Mounting nested directories from multiple servers in NFS. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved

10 Figure 11-13. A simple automounter for NFS.
Automounting (1) Figure A simple automounter for NFS. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved

11 Figure 11-14. Using symbolic links with automounting.
Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved

12 Semantics of File Sharing (1)
Figure (a) On a single processor, when a read follows a write, the value returned by the read is the value just written. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved

13 Semantics of File Sharing (2)
Figure (b) In a distributed system with caching, obsolete values may be returned. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved

14 Semantics of File Sharing (3)
Figure Four ways of dealing with the shared files in a distributed system. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved

15 Figure 11-18. NFSv4 operations related to file locking.
Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved

16 File Locking (2) Figure The result of an open operation with share reservations in NFS. (a) When the client requests shared access given the current denial state. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved

17 File Locking (3) Figure The result of an open operation with share reservations in NFS. (b) When the client requests a denial state given the current file access state. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved

18 Client-Side Caching (1)
Figure Client-side caching in NFS. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved

19 Client-Side Caching (2)
Figure Using the NFSv4 callback mechanism to recall file delegation. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved

20 Figure 11-28. The NFS security architecture.
Security in NFS Figure The NFS security architecture. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved

21 Figure 11-29. Secure RPC in NFSv4.
Secure RPCs Figure Secure RPC in NFSv4. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved

22 Access Control Figure The various kinds of users and processes distinguished by NFS with respect to access control. Tanenbaum & Van Steen, Distributed Systems: Principles and Paradigms, 2e, (c) 2007 Prentice-Hall, Inc. All rights reserved