The major differences from Limi's instructions on Apache 1.3 were:

• In order to get apache proxying the requests the following line needs to be uncommented in the httpd.conf:

    LoadModule proxy_http_module modules/mod_proxy_http.so
  

• The following modules are also needed to get the caching working. They may not appear in your httpd.conf so if not, you'll have to add them:

    LoadModule disk_cache_module modules/mod_disk_cache.so
    LoadModule cache_module modules/mod_cache.so
  

• The following setting in httpd.conf file was not enough:

    CacheRoot "/var/cache/artpropensity.com"
  

It must be proceeded by: CacheEnable disk /

so that it looks like:

  CacheEnable disk /
  CacheRoot "/var/cache/artpropensity.com"

• I also had to set explicit IP's and hosts in my /etc/hosts file, as in:

    192.168.10.10 www.artpropensity.com artpropensity.com 
  

This is so that the following settings in the httpd.conf file will get resolved properly:

  ProxyPass / http://www.artpropensity.com:9080/VirtualHostBase/http/www.artpropensity.com:80/artpropensity/VirtualHostRoot/
  ProxyPassReverse / http://www.artpropensity.com:9080/VirtualHostBase/http/www.artpropensity.com:80/artpropensity/VirtualHostRoot/

• Using "wget -sS ..." as command line also did not work for me. I ended up running a browser on an external server using X-windows. I set the browser to no-cache (check for new page each time) to make sure that it did not cache items and instead made a full request to Apache each time it accessed the site. I also used your advice and performed:

    $ tail -f Z2.log
  

to make sure that Plone was not serving up .js, .css, .gif, etc. and instead Apache was serving them up once cached. I did notice 304's on some items, but I assume that's because the browser was set to no-cache and it forced Apache to check with Plone to see if the file had changed.

I noticed a speed increase from 4 requests/sec to an average of 300 using Apache 2 caching