Improving NFS performance over wireless links

Abstract

NFS is a widely used remote file access protocol that has been tuned to perform well on traditional LANs which exhibit low error rates. Users migrating to mobile hosts would like continued remote file access via NFS. However, low bandwidth and high error rates degrade performance on mobile hosts using wireless links, hindering the use of NFS. We conducted experiments to study the behaviour of NFS in a wireless testbed. Based on these experiments, we incorporated modifications into the mobile NFS client. This paper presents two mechanisms which improve NFS performance over wireless links: an aggressive NFS client and link-level retransmissions. Our experiments show that these mechanisms improve response time by up to 62%, which brings the performance to within 5% of that obtained in zero error conditions.