Parallel IO on ARCHER2

File input and output can become bottlenecks for parallel programs running on large numbers of processors. In this work we investigate how to increase the MPI-IO performance on ARCHER2, the UK National HPC service, using the Cray Lustre lockahead options which have not been previously investigated on this system. We then investigate the performance of ADIOS2, a more modern parallel IO library, and look at the performance of IO from a real HPC application rather than a synthetic benchmark.