Sensitivity of Cluster File System Access to I/O Server Selection

This paper describes measurement tests of Parallel Virtual File System (PVFS) and Network File System (NFS) over commodity Linux cluster connected with Myrinet. PVFS stores file by storing fixed-size stripes in round-robin fashion cross I/O servers. The number and identity of I/O servers is selectable at execution time. Our evaluation includes testing with varying number and configuration of servers and varying client request patterns. Results show that NFS performance is limited by the disk and network throughput of the server. Both NFS and PVFS are affected by the number of clients in the system and when the I/O nodes also serve as clients. For fixed number of servers, PVFS performance is improved if the client nodes do not participate as servers. For the workloads tested, PVFS performance improves as the number of clients and servers increases to the maximum number of nodes on the system.