Our current round-trip test server is bogging down with the large DB it has accumulated by now. This makes it the bottleneck in rt testing, leaving the clients mostly idle.
Much of the db size is XML-encoded old test results, which we don't really need any more. Moving those large results to a separate db might make it easier to truncate old results by simply re-creating the result xml db.
Apart from the DB size, the node.js sqlite bindings we use don't seem to help performance either. IIRC they don't support transactions and other performance-improving features / pragmas. We mainly used sqlite because it was easy to get started, but it might make sense to re-evaluate that choice. A separate DB server would at least make it possible to use two cores instead of just one.