> You could ship a Rack to every Region, State, Nation, Jurisdiction or Local ISP and Exchange and be done with it.
And when a single rack is down the whole region might be impacted negatively. The blast radius of such a setup would be huge!
As a CDN you really want to avoid this. Even for regular operations you need to be able to afford some servers going out of service for software update and other maintenance - without impacting availability, latency for users (the latter would happen if you route them to a complete different region), or infrastructure costs (which increase if you can't serve data from as close to the user as possible anymore, and have to pay for additional networking fees).
All major CDN providers have hundreds of regions (all with multiple hosts), and you can't really avoid the former. You could run less hosts per region, but whether 1 is the feasible will depend a lot on other parts of your system.
And when a single rack is down the whole region might be impacted negatively. The blast radius of such a setup would be huge!
As a CDN you really want to avoid this. Even for regular operations you need to be able to afford some servers going out of service for software update and other maintenance - without impacting availability, latency for users (the latter would happen if you route them to a complete different region), or infrastructure costs (which increase if you can't serve data from as close to the user as possible anymore, and have to pay for additional networking fees).
All major CDN providers have hundreds of regions (all with multiple hosts), and you can't really avoid the former. You could run less hosts per region, but whether 1 is the feasible will depend a lot on other parts of your system.