A few off the points is applicable at much lower QPS than 1 million, especially in a virtualized environment such as EC2. For example, I've had some issues wit

A few off the points is applicable at much lower QPS than 1 million, especially in a virtualized environment such as EC2. For example, I've had some issues with CPU (on core 0) saturation for soft interrupts on EC2, related to processing network packets.