Recently, I came across a couple of really terrific presentations on redo internals and redo reduction by Julian Dyke. If you have any interest in some of the more subtle details of Oracle redo, I highly recommend you take some time to go through these presentations. In typical Julian Dyke form, they are lucid, concise and very informative.
They are available on the web
free of charge. Check them out and let me know what you think!