Brian,
If you accepted all the default variables during the install, there is an OSSV client database that gets created/stored on the C: drive. This database size is roughly 2-3% of the dataset sizes being backed up. You can determine where the OSSV database is being stored by looking at the "snapvault.cfg" file, or the OSSV Configurator GUI. This database is also backed up as part of every OSSV backup session.
Thanks!
Jeremy