In Apache 2.2 there are 2 types of advanced caching available:
– Memory based caching
– Disk based caching
Here are some tips and links related to the disk cache feature:
APACHE 2.2 cache cleaning command:
Recomended to run regularly from cron job
# Runs as cron job, in nice mode, and limits the cache to 200MB
htcacheclean -n -t -p /var/www/cache -l 200M
Apache caching articles
http://blog.josepruano.com/2008/04/logging-apaches-cache-modules.html
http://www.alachisoft.com/ncache/dynamic_clustering.htm
http://askapache.com/2006/htaccess/speed-up-sites-with-htaccess-caching.html