A Tune challenge from Foundations. Your shop runs in the United States, with Europe on standby to save money. At 30 seconds the whole US region goes dark, and the router takes five seconds to move everyone to Europe. From ten seconds after the outage, fewer than 2 in 100 requests may fail. Make the standby ready, and spend as little as you can.
The design you start with: p99 116ms, 0% of requests failing, 368/s answered.