This is a spin-off of a HELP ticket that the execution team received. The MongoDB layer was using a lookaside score threshold of 50 at the time – it has since been raised to 95 --, but it doesn't make sense why the lookaside score would be high at all when so little cache is in use.

We were hoping you could figure out why the lookaside score when up. Perhaps delineating some kind of contract that the lookaside score follows would be helpful as well, since the MongoDB layer has become dependent on it.