For decades, HPC applications used a shared parallel file system for input/output (I/O), but the recent addition of new storage devices in systems—burst buffers, for example—has enabled the creation of a storage hierarchy. The hierarchy can be arranged such that in-system storage is the first level, and the parallel file system the second. For optimal performance, applications must change along with the architectures.

In this podcast episode (11:28) produced by the Exascale Computing Project, LLNL’s Kathryn Mohror and ORNL’s Sarp Oral talk about the open source tool UnifyFS, which can provide I/O performance portability for applications, enabling them to use distributed in-system storage and the parallel file system.