Can you tell from production.log what are the controllers that are being used? What’s the workload? If you are running a monitoring system, ideally, can you tell when a process saw a spike so we can correlate this with logs in the production.log?
We really need to narrow this down a bit, Foreman as many other Ruby apps do have memory leaks, we are pretty successful with finding them and fixing them. But there must be something special with your setup, 3.1 is going through heavy testing at the moment and we haven’t see such big problems so far.