An-I Andy Wang and
UCLA, The Laboratory for Advanced Systems Research
Rajive L. Bagrodia
UCLA, Parallel Computing Laboratory
Optimistic replication of data is becoming increasingly popular in mobile environments, but its performance and scaling characteristics are not well understood. This paper presents a simulation evaluation of optimistically replicated filing in a mobile environment. We first compare full and selective optimistic replication systems to capture the properties required for scaling. We then show that the presence of portable computers in optimistically replicated filing systems achieves a 60-percent cost reduction (e.g., computing resources) with only a 10-percent degradation of service quality (e.g., consistency of data perceived by users). This finding reveals certain similarities between the network disconnection interval and frequency of data synchronization. The research suggests new guidelines for design of optimistic replication systems.