Abstract :
One of the primary mass storage systems in use at the Los Alamos National Laboratory (LANL) is the Common File System, or CFS. CFS went into production in 1979, servicing supercomputer environments, and later was expanded for use with a broader networked workstation environment. It is now used by a very large user population at LANL. It can be used by any employee for storage purposes, and is used by all of the large supercomputers at LANL. CFS is being phased out for the supercomputing environment due to the need for a more scalable mass storage system design. To our benefit, records have been kept for the last seven years of all activity on CFS. A statistical analysis of these records has been performed, to understand how the mass storage system was used over a long period of time. Example usage statistics include maximum and average file sizes, data rates, and bytes moved for each month. Trends and observations about these usage statistics will be presented. The paper will also present some study in the effects of environmental changes and their implications for CFS. An example of an environmental change question is: how does new media technology affect the usage or management of the system? Study of the performance of the storage system over this long period of time will also be presented. Characterization of performance and how migration, environmental factors, and usage-affected data rate performance as well as time-to-first-byte performance is examined. Some conclusions about usage and its effect on planning, design, and operation of mass storage systems will be discussed. It is hoped that the analysis of actual long run usage data of a mass storage system in a demanding supercomputing environment will provide interesting lessons that can be applied to the planning, design, and operation of future mass storage systems.
