>then you can sure as hell "spin up more synchronous workers". And even with a free load balancer like HAproxy, you can have a set of fallback machines usable

>then you can sure as hell "spin up more synchronous workers". And even with a free load balancer like HAproxy, you can have a set of fallback machines usable by any backend that's over-capacity, with the spin-up being on-demand, like, say, with Apache workers.