capacity
termops culturenetworking
How much load a system can carry before its behaviour degrades - which is not the same as the number on the specification.
The useful figure is the point where response time starts climbing, not the point where something stops answering, and those are far apart: queues grow non-linearly, so a system at ninety per cent utilisation behaves nothing like one at fifty, and the last ten per cent of nominal capacity is usually unusable in practice. Planning against the rated number rather than the measured knee is the standard way to discover this, always at the least convenient moment.
Also known as: capacity planning