I/O performance is just one of many characteristics that impact performance and from experience the one you least need to worry about. RAID 0 across multiple high-end NVME drives with OS file caching is going to be more than fast enough for most use cases.
The issue is running out of CPU performance and being able to seamlessly scale up/down compute with live running workloads.
But ... we are ... basically by definition. Vanishing little projects actually need cloud scale infrastructure.
And, to address your previous statement: one beefy server is actually pretty scalable. Soft threads spin up in microseconds to serve incoming requests, communication between threads is blazing fast, caching is simpler on one machine, etc. You don't even have to worry to much about scaling, the CPU just throttles itself when there is no load.
And every once in a while you just upgrade to the next gen beefy machine.
I/O performance is just one of many characteristics that impact performance and from experience the one you least need to worry about. RAID 0 across multiple high-end NVME drives with OS file caching is going to be more than fast enough for most use cases.
The issue is running out of CPU performance and being able to seamlessly scale up/down compute with live running workloads.