Sorry to keep coming back, I don't want to start a flame war here. Difficulty of horizontal scaling is a property of two things: 1. how your solution is desi

Sorry to keep coming back, I don't want to start a flame war here. Difficulty of horizontal scaling is a property of two things: 1. how your solution is designed (your point, and I agree this is often done poorly) 2. the problem / work-load you are trying to scale (my point). It might be that your problem does not "shard" very easily. You cannot fix this with solution architecture, at least not easily. Horizontal scaling of a relational database is very difficult, for example. Edit: Another example. Can you rewrite NGINX in a slower language and use horizontal scaling to fix it? Of course not, because that horizontal scaling would itself leverage NGINX (or something like it)!