> At some scale getting a bigger machine either doesn't make financial sense or is just not possible to implement efficiently.
You don't even need to get scaling into the picture.
You do not get any form of fault tolerance by deploying stuff in a single lonely box. If you care about reliability and resilience, you have to have multiple deployments up and running at the same time.
Also, you already have a distributed system if you have a browser calling your server.
And lastly, if you happen to manage an service used globally or regionally and perceived performance matters then you have no good alternative to have regional deployments.
You don't even need to get scaling into the picture.
You do not get any form of fault tolerance by deploying stuff in a single lonely box. If you care about reliability and resilience, you have to have multiple deployments up and running at the same time.
Also, you already have a distributed system if you have a browser calling your server.
And lastly, if you happen to manage an service used globally or regionally and perceived performance matters then you have no good alternative to have regional deployments.