I am curious about the relative sizes of people's venti
servers, how much data they have stored, and how
quickly they are filling.

Please run

hget http://my-venti-url/storage >/tmp/v
hget http://my-venti-url/index >>/tmp/v

mail -s 'venti survey' rsc@swtch.com
In a week or so I will post a summary.

Thanks.
Russ