@pmwkee: http://sphia.org/pv12.html doesn't tell us the scaling characteristics. The cited performance page is DB at steady state of 6.0M keys. how does it behave under dynamic load? Various scenarios to help your potential users determine if the software is a good fit for their use-case, would be helpful.

Glanced at the code and the arch doc. Looks promising and shows careful crafting. Well done!