Measurement and simulation based performance analysis of parallel I/O in a high-performance cluster system

This paper presents a measurement and simulation based study of parallel I/O in a high-performance cluster system: the Pittsburgh Supercomputing Center (PSC) DEC Alpha Supercluster. The measurements were used to characterize the performance bottlenecks and the throughput limits at the compute and I/O nodes, and to provide realistic input parameters to PioSim, a simulation environment we have developed to investigate parallel I/O performance issues in cluster systems. PioSim was used to obtain a detailed characterization of parallel I/O performance, in the high performance cluster system, for different regular access patterns and different system configurations. This paper also explores the use of local disks at the compute nodes for parallel I/O, and finds that the local disk architecture outperforms the traditional parallel I/O over remote I/O node disks architecture, even when as much as 68-75% of the requests from each compute node goes to remote disks.