Graceful degradation by turning off optional features and making the critical path (order completion funnel) as lightweight as possible by reducing costs (# of results fetched/scored, turning off reco etc) was the best way to scale systems seeing 3x higher peaks year over year; and 10x higher peak during flash sales compared to normal periods, especially without breaking the bank trying to provision that much capacity.
p.s. - btw, no cloud has that much elastic capacity.
p.s. - btw, no cloud has that much elastic capacity.