A case study of large-scale parallel I/O analysis and optimization for numerical weather prediction system
We implement two parallel I/O strategies based on MPI-IO and ADIOS in GRAPES. MPI_AMR in ADIOS is ideal if aggregator number is twice or four times that of OSTs. 114MB per OST is the optimal size for each I/O on the Tianhe-1A system. 8 time-step aggregation by MPI_AMR reaches 7.69GB/s, 68.4% of theoretical bandwidth. There is an optimal number of OSTs to distribute one MPI file for good I/O performance.
parallel i/o mpi-io adios grapes numerical weather forecast i/o optimization