I recently came across Colm MacCarthaigh’s Apache tuning presentation and technical white paper:
Tuning Apache and Linux for performance presentation:
http://www.stdlib.net/~colmmacc/Apachecon-EU2005/scaling-apache-presentation.pdf
Tuning Apache and Linux for performance paper:
http://www.stdlib.net/~colmmacc/Apachecon-EU2005/scaling-apache-handout.pdf
Colm is an admin at heanet, which runs some of the busiest web servers in the world. The presentation and white paper cover the entire software stack, which includes kernel, file system and of course Apache web server tuning. These are must reads for website administrators.