I'm wondering what the metric will display that is useful? Volume is dependent upon purpse of the distro. (CentOS & Debian stable will track low volume - their purpose is to provide a predictable environment. Fedora & Debian unstable will track a higher, and fairly variable volume). Do you plan to track against initial volume? When I last looked Debian's full distro was 14 CDs (with a single CD net install option) Again driven by purpose.