An Analysis of File Migration in a Unix Supercomputing Environment
Ethan L. Miller, Randy Howard Katz · 1992
The supercomputer center at the National Center for Atmospheric Research (NCAR) migrates large numbers of files to and from its mass storage system (MSS) because there is insufficient space to store them on the Cray supercomputer’s local disks. This paper presents an analysis of file migration data collected over two years. The analysis shows that requests to the MSS are periodic, with one day and one week periods. Read requests to the MSS account for the majority of the periodicity; as write requests are relatively constant over the course of a week. Addition-ally, reads show a far greater fluctuation than writes over a day and week since reads are driven by human users while writes are machine-driven. 1 Introduction* Over the last decade, computers have made incredible gains in speed. This speedup has encouraged the pro-cessing of larger and larger amounts of data; however, storing this data on magnetic disk is not feasible.