We are trying to deploy mongrel instances on a machine. What is the optimal number of mongrel instances for a server? Since an instance can handle concurrent connections, I do not see any benefit in starting more than 1 per core. Any more than that and the threads will just fight for CPU. Our predecessors have assigned 10 instances for 4 cores, but I think it will just cause CPU contention. Any definitive answers / opinions? I have seen this question: How many mongrel instances? But it is really not specific enough.