phpservermon/puphpet/puppet/modules/apache/templates/mod/disk_cache.conf.erb

<IfModule mod_proxy.c>
  <IfModule mod_disk_cache.c>
     CacheEnable disk /
     CacheRoot "<%= @cache_root %>"
     CacheDirLevels 2
     CacheDirLength 1
  </IfModule>
</IfModule>