ABSTRACT: The growth requirements for unstructured data are seemingly insatiable. High capacity/high density storage for technical and scientific applications continues to rapidly evolve. New systems and technologies are providing capacity and performance capabilities that were unthinkable a few years ago. The site-wide storage system at Los Alamos National Labs is being enhanced to support the new Cielo supercomputer system. Panasas will detail the PAS HC system that provides the storage infrastructure for the Cielo system and the 5 other supercomputers including RoadRunner on a single site-wide system that provides maximum I/O performance at minimum capital and operational cost.