One way to look into scalability is by understanding Scale Cube. In the book The Art of Scalability: Scalable Web Architecture, Processes, and Organizations for the Modern Enterprise, Martin L. Abbott and Michael T. Fisher defines Scale Cube to view and understand system scalability. Scale Cube applies to microservice architectures as well:
In this three-dimensional model of scalability, the origin (0,0,0) represents the least scalable system. It assumes that the system is a monolith deployed on a single server instance. As shown, a system can be scaled by putting the right amount of effort in three dimensions. ...
