Like SSDs bring any new angle to this.

> You can't run a high-throughput database on spinning disks unless you disregard data integrity

Of course you can. That's the way it was and still is done. I'd say one can't run a database with any data integrity unless there are disks spinning somewhere very near.

I'd take another box for like $40 there just for the replica, which would sit mostly idle anyways.

But piling on CDNs, clouds and variuos other opex and indeterminate risks instead of some thinking out of this little cloud shoebox is just baffling.

Spinning disks lose data integrity? You will be surprised where the cloud servers store your backups then. They are doing 80TB/month, you don't need 1GB/s nvme for that(assuming everything is uncached).