OS Distributed File Systems

Unix, Coherent & Session semantics

Unix, Transaction & Session semantics

Coherent, Transaction & Session semantics

Session, Coherent semantics

All replicas are identical at all times

Replicas are perceived as identical only at some points in time

Users always read the most recent data in the replicas

All of the mentioned

Idempotency requirement

Encryption of keys

File locking mechanism

Cache consistency

fixed routing

virtual routing

dynamic routing

all of the mentioned

Complicated implementation

Deadlock cannot occur easily

Bottleneck

All of the mentioned

bidirectional

unidirectional

both bidirectional and unidirectional

none of the mentioned

Modified

Removed

Added

All of the mentioned

stateless file service

stateful file service

both stateless and stateful file service

none of the mentioned