wiredtiger/wiredtiger.github.com — Issue #142: Calculate the physical size of a snapshot 
Author: wiredtiger
Created: 2012-01-31 19:07:40+00:00
State: open

For the most recent snapshot, this is relatively simple: walk through the free lists of all snapshots and do a simple numerical calculation: total file size - sum of freelists. This may be all that is required.