The only real solution to overload (that is, the eventuality of the system not having enough capacity), in modern systems, is autoscaling. Nobody seems to talk about this, I guess because it's taken for granted? But you can literally just keep adding capacity now. We didn't really have that before the cloud; you had the servers you bought, and maybe you'd rush to repurpose some servers to add capacity. Now an algorithm just adds servers magically when your load gets high.
Of course the system still has limits. But if you go from zonal to regional to global autoscaling, and you architect specifically to scale up each point in the system using autoscaling, it kind of doesn't have a limit? (that any one product would hit, at a global level)
In the past I have spun up a duplicate distributed system in another region and just split the traffic between the two. IaC is crazy.
Of course the system still has limits. But if you go from zonal to regional to global autoscaling, and you architect specifically to scale up each point in the system using autoscaling, it kind of doesn't have a limit? (that any one product would hit, at a global level)
In the past I have spun up a duplicate distributed system in another region and just split the traffic between the two. IaC is crazy.