Impact of delays in parallel I/O system: an empirical study

Performance of I/O intensive applications on a multiprocessor system depends mostly on the variety of disk access delays encountered in the I/O system. Over the years, the improvement in disk performance has taken place more slowly than the corresponding increase in processor speeds. It is therefore necessary to model I/O delays and evaluate performance benefits of moving an application to a better multiprocessor system. We perform such an analysis by measuring I/O delays for a synthesized application that uses a parallel distributed file system. The aim of this study is to evaluate the performance benefits of better disks in a multiprocessor system. We report on how the I/O performance would be affected if an application were to run on a system which would have better disks and communication links. In this study, we show a substantial improvement in the performance of an I/O system with better disks and communication links with respect to the existing system.