[grizzles]

I think you've documented some of the issues on the Titan Limitations page. For us, we couldn't get Titan to work properly, which we documented in the Issue Tracker. That lead me to the conclusion that Titan was just too complex because from my perspective it's obvious that you guys are spreading yourselves too thin with the 7 different backends.

Why do you need both a BerkeleyDB and PersistIt backend? At the absolute most you should have 2 or 3. Single Machine, AP Cluster, ACID Cluster.

7 backends means 7 different database products, with the same API facade. Duh right? Well the problem is that constrains your API to a least common denominator feature set, limiting access to the unique attributes and capabilites of the underlying backend. Not to mention completely abstracting away memory/disk issues. This is a really big issue with your approach. You have some sunken costs here but I think eventually you will see the value in tightening up your focus.