A newly enhanced I/O subsystem will support the nation’s first exascale supercomputer, the HPE Cray Frontier system, and the Oak Ridge Leadership Computing Facility (OLCF). The computational might of exascale computing, expected to have top speeds of 1 quintillion — that’s 1018, or a billion billion — calculations per second, promises to enable breakthrough discoveries across the scientific spectrum when Frontier, set to power up by year’s end, opens to full user operations in 2022, from the basics of building better nuclear reactors to insights into the origins of the universe. The I/O subsystem will consist of two major components: an in-system storage layer and a center-wide file system. The center-wide file system, called Orion, will use open-source Lustre and ZFS technologies.