JL Computer Consultancy

This attached file is in Powerpoint 7 format. The size is 220 Kb.

The content is a presentation given to the UNIX SIG of the the UK Oracle User Group in March 1999, and was based on a presentation made to the UK Annual Conference of the UKOUG the previous year.

There are often discussions on the Oracle newsgroups and listservers about the relevant performance benefits and costs of raw devices over file systems, but these are rarely backed up by hard facts. The presentation is a very tight summary of a series of experiments aimed at discoverering how significant the difference might be, and when it might be worth worrying about it.

The conclusions of the presentation are:

• The interaction between Oracle and a file-system can be quite dramatic
• Fast file systems (such as Veritas) can be of significant benefit over standard Unix file systems
• Raw devices can be significantly better than file system in specific circumstances
• There are strategies for reducing file system contention if you want to avoid raw.

Whilst this article is in the form of a Powerpoint 7 presentation, most of the important content is in the notes pages. The slides themselves add a little colour. There is an associated note, previously published on this site, with the full text of a pair of C programs that can be used to reproduce the timing experiments described in the paper.

If anyone would like to have the presentation in Powerpoint 4 format, contact me on jonathan@jlcomp.demon.co.uk

I have also uploaded a copy of the file compressed to 36 Kb using the Zip facility supplied by Oracle on the NT 8.0.4 release: the matching Unzip (90K) utility, and a zipped copy (47K) of Zip itself are available if you need them.

Download 220K article

Download 36Kb compressed article