Scheduling Write Backs For Weakly-Connected Mobile Clients

The emerging demand for mobile computing has created a need for improved file system support for mobile clients. Current file systems with support for mobility provide availability through file replicas cached at the client. However, the wide range in the quality of network connections a mobile client may experience makes cache management a complex task.One important cache management decision is how (and when) modifications that have been made to cached files at a weakly-connected client can and should be propagated back to the file server. This paper presents the results of a trace-driven simulation study of two write-back scheduling policies: a simple statistical policy and a more explicit "reader preference" policy. Emphasis is placed on the interaction between the workload created by loading files demanded by a user and background writes performed to maintain file consistency.