Models and Measurements of File System Performance

Abstract:

File system buffering strategies can produce unexpected system behavior. For instance, writing one byte to a file can take more than twice as long as writing 4096 bytes to the same file. To examine this curious phenomenon and other aspects of file system performance, we develop models for file system behavior which factor in contributions of processor speed and buffer cache organization. These models agree very nicely with a set of performance measurements conducted on a VAX-11/750 running the UNIX 4.3 BSD
operating system. We use these same models to predict the performance of recently proposed parallel mass storage architectures. We demonstrate that these architectures can potentially provide orders of magnitude more file system bandwidth than conventional non-parallel systems now provide.