What is Scalability Anyway? Do words mean things? Why? What does scalable mean? As systems designers, builders, and researchers, we use that word a lot. We kind of all use it to mean that same thing, but not super consistently. Some include scaling both up and down, some just up, and some just down. Some include both scaling on a box (vertical) and across boxes (horizontal), some just across boxes. Some include big rack-level systems, some don’t. Here’s my definition: A system is scalable in the...