[caudicus]

So what does exactly equal scaling then?

I'm not disagreeing that scaling isn't only caching, but it's often a component just like anything else. Caching often helps scaling, as do multiple databases, working out bottlenecks in code...whatever else.

[zepolen]

Scaling = Increasing capacity indefinitely by adding more nodes.

Caching is not scaling because by definition, it depends on a backend to provide it data.

If the backend is a database then sure, you can increase capacity by ~10x (assuming a ~90% cache hit rate), but after that, throwing more caching nodes at the problem won't do a thing if your database itself isn't scalable.

All a cache does is increase speed at decreased costs, but it is not in itself a scaling solution.