Performance and scalability of atmospheric models on Linux systems

Today many computational problems are within the reach of more people due to the advances in computers designed for the mass market. Each year computer companies deliver higher computer speeds, more memory, larger disks, and faster networking at a decreased cost. This reality has led many to build large clusters of Pentium class computers interconnected with fast networking, programmed with message passing APIs, and run under the Linux operating system. These high performance clusters built with commodity off the shelf (COTS) hardware have been assembled for much less than the yearly maintenance costs of large, commercial parallel processor machines. Universities and research organizations with modest budgets can now use computer clusters to offer compute performance previously only attainable on expensive mainframe computers. The Naval Research Lab's Marine Meteorology division has starting evaluating Linux clusters as possible replacement platform, to run their weather models at the lab and at the U.S.Navy's regional data centers. This paper describes our experiences with this effort, outlining some of the practical considerations, and comparing the performance against similar cases run on the SGI and IBM computers.