[dh997]

There's only so many TB of ram / disk and cores that can fit in one box for sensible cost, whereas it's usually far cheaper and less limited to just add more boxes, plus the SPoF of one giant box.

It usually indicates developer/provider laziness / cheapness / lack of imagination when people say something "can't" be done. Have they even tried? Most real problems are diagonalizable. Plus any shop using RDMA and fast infiniband instead of Ethernet dont have to worry as much about node-to-node latency.

There is no magic solution for all use cases, but scaling veritically tends to encounter budget or technical limits where a little forethought beforehand could have scaled using modern tools instead of shifting burden down the stack.

If you're LMAX, scale up... looking for ET in radio signals, scale out.