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PROPRIETARY MATERIAL. © 2007 The McGrawHill Companies, Inc. All rights reserved. No part of this PowerPoint slide may be displayed, reproduced or distributed in any form or by any means, without the prior written permission of the publisher, or used beyond the limited distribution to teachers and educators permitted by McGrawHill for their individual course preparation. If you are a student using this PowerPoint slide, you are using it without permission.
Chapter 19:
Distributed File Systems
Dhamdhere: Operating Systems— A ConceptBased Approach, 2 ed
Slide No: 1 Copyright © 2008
Design issues in Distributed File Systems
• Transparency of a file system
– A user need not know the location of a file in the system
* Location transparency: The name of a file should not reveal its location
Provides user convenience
* Location independence: File system should be able to change the location of a file without having to change its name
Enables the file system to optimize its own performance
Chapter 19:
Distributed File Systems
Dhamdhere: Operating Systems— A ConceptBased Approach, 2 ed
Slide No: 2 Copyright © 2008
Design issues in Distributed File Systems
• Fault tolerance
– Two techniques are used to ensure that a fault does not disrupt operation of a file system
* Journaling technique may be used to ensure consistency of meta data
* Stateless file server design eliminates the need to maintain consistency of meta data
Chapter 19:
Distributed File Systems
Dhamdhere: Operating Systems— A ConceptBased Approach, 2 ed
Slide No: 3 Copyright © 2008
Design issues in Distributed File Systems
• Performance
– File system performance has two aspects
* High efficiency
File caching boosts efficiency by reducing network traffic * Scalability
Response time should not degrade as system size grows Special scalability techniques are employed
» Clusters of computers
» Distributed locking techniques
Chapter 19:
Distributed File Systems
Dhamdhere: Operating Systems— A ConceptBased Approach, 2 ed
Slide No: 4 Copyright © 2008
Basics of file processing in a DFS
• A user or process that accesses a file is called a client
• When the client opens a file, the DFS finds its location during name resolution • DFS sets up the arrangement involving the client and file server agents
• This arrangement is analogous to a remote procedure call (RPC)
Chapter 19:
Distributed File Systems
Dhamdhere: Operating Systems— A ConceptBased Approach, 2 ed
Slide No: 5 Copyright © 2008
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