I used to send something like 250k a minute complete with delivery report processing from a single machine running a bunch of other services like 10 years ago.
But average latency is not the whole picture; tail latency is. For good tail latency and handling of spikes, you have to have a sizable "untapped" reserve of performance.
But average latency is not the whole picture; tail latency is. For good tail latency and handling of spikes, you have to have a sizable "untapped" reserve of performance.