Reflector: a fine-grained I/O tracker for HPC systems

We present Reflector, to support both high-level and low-level I/O monitoring through user-defined interfaces such as HDF5 and NetCDF in addition to POSIX- and MPI-IO. We evaluate Reflector on both an on-premises 500-core HPC cluster and a leadership-class supercomputer at the Lawrence Berkeley National Laboratory. Preliminary results are promising as the system prototype incurs negligible performance overhead and clearly illustrates the I/O patterns and bottlenecks of multiple applications.