Electrical Engineering
      and Computer Sciences

Electrical Engineering and Computer Sciences

COLLEGE OF ENGINEERING

UC Berkeley

Beating the I/O Bottleneck: A Case for Log-Structured File Systems

John K. Ousterhout and Frederick Douglis

EECS Department
University of California, Berkeley
Technical Report No. UCB/CSD-88-467
October 1988

http://www.eecs.berkeley.edu/Pubs/TechRpts/1988/CSD-88-467.pdf

CPU speeds are improving at a dramatic rate, while disk speeds are not. This technology shift suggests that many engineering and office applications may become so I/O-limited that they cannot benefit from further CPU improvements. This paper discusses several techniques for improving I/O performance, including caches, battery-backed-up caches, and cache logging. We then examine in particular detail an approach called log-structured file systems, where the file system's only representation on disk is in the form of an append-only log. Log-structured file systems potentially provide order-of-magnitude improvements in write performance. When log-structured file systems are combined with arrays of small disks (which provide high bandwidth) and large main-memory file caches (which satisfy most read accesses), we believe it will be possible to achieve 1000-fold improvements in I/O performance over today's systems.


BibTeX citation:

@techreport{Ousterhout:CSD-88-467,
    Author = {Ousterhout, John K. and Douglis, Frederick},
    Title = {Beating the I/O Bottleneck: A Case for Log-Structured File Systems},
    Institution = {EECS Department, University of California, Berkeley},
    Year = {1988},
    Month = {Oct},
    URL = {http://www.eecs.berkeley.edu/Pubs/TechRpts/1988/5760.html},
    Number = {UCB/CSD-88-467},
    Abstract = {CPU speeds are improving at a dramatic rate, while disk speeds are not. This technology shift suggests that many engineering and office applications may become so I/O-limited that they cannot benefit from further CPU improvements. This paper discusses several techniques for improving I/O performance, including caches, battery-backed-up caches, and cache logging. We then examine in particular detail an approach called log-structured file systems, where the file system's only representation on disk is in the form of an append-only log. Log-structured file systems potentially provide order-of-magnitude improvements in write performance. When log-structured file systems are combined with arrays of small disks (which provide high bandwidth) and large main-memory file caches (which satisfy most read accesses), we believe it will be possible to achieve 1000-fold improvements in I/O performance over today's systems.}
}

EndNote citation:

%0 Report
%A Ousterhout, John K.
%A Douglis, Frederick
%T Beating the I/O Bottleneck: A Case for Log-Structured File Systems
%I EECS Department, University of California, Berkeley
%D 1988
%@ UCB/CSD-88-467
%U http://www.eecs.berkeley.edu/Pubs/TechRpts/1988/5760.html
%F Ousterhout:CSD-88-467