1. Ch 6. Summary
Gang Shen

2. Goal
Discuss fundamental concepts and design issues for the distributed file system.[1]

3. 6.1 DFS Characteristics Dispersed clients Dispersed files, data
Multiple users
Replicated files and data
Transparent
Scalable
Fault tolerant
Efficient

4. 6.2 DFS design Hierarchy files structure File mounting protocol
Explicit mounting, manual
Boot mounting, boot up time mounting
Auto mounting, mounting at use
Distribute state information between server and clients. Stateless or stateful server

5. 6.2 continue File access Space multiplexing, multiple copy of file
Remote access
Cache access
Download/upload access
Time multiplexing, concurrent control. Same file different time
Simple RW
Transaction
session

6. 6.2 continue File sharing semantics
Unix, update propagated immediately
Session, delayed update
Transaction, delayed update

7. 6.3 Transactions and concurrency control
Transaction process system, includes
Transaction Manager
Schedule
Object Manager
Serializability
Concurrency control
Two phase locking
Timestamp ordering
Optimistic

8. 6.4 Data and file Replication
Architecture
One-copy serializability
Quorum voting
Gossip update

9. Reference
[1] Randy Chow,Theodore Johnson, “Distributed Operating Systems & Algorithms”, 1998