if you push your design to the limits of scalability, then you gonna hit a wall at some point (IO, memory or CPU) and as long as your application is not based o

if you push your design to the limits of scalability, then you gonna hit a wall at some point (IO, memory or CPU) and as long as your application is not based on CPU intensive calculations (simulations, calculus, ...) most of the time IO is the bottleneck, network or disk. However, I am not that experienced in distributed applications and would appreciate reading the opinions from more experienced engineers.