> First off, this is obviously false. If you can serve 9req/s and you're getting 10req/s the size of the queue depth is growing at a rate of 1req/s. It's not st

> First off, this is obviously false. If you can serve 9req/s and you're getting 10req/s the size of the queue depth is growing at a rate of 1req/s. It's not stationary. I haven’t formally studied any queuing theory, but I think: 1. The rule assumes you have enough processing power to service the average load (otherwise it fails catastrophically like you mentioned) 2. The rule is trying to model the fluctuations in the pending load (which might determine wait time or whatever else).