I was recently asked what the difference was between “scaling up” and “scaling out.” I thought, “why not draw a cartoon to illustrate?” So below is my attempt at drawing a cartoon to show the difference between the two. (By the way, if you haven’t figured it out, those are servers flexing their biceps. Yes, they have stick legs. I’ve been telling them to do squats but they don’t listen!) :)
SQL Server Scale Up vs Scale Out
Horizontal vs. Vertical
So in a nutshell, here is the difference:
Scaling out hardware is also called, “horizontal” growth. You add existing servers, hardware, etc. to the currently setup. So if you have one server, you add another server to that and load balance, etc.
Scaling up hardware is also called, “vertical” growth. You “beef up” your current server specs. So if you have 16GB of RAM, you upgrade to 32GB of RAM, you put in a faster SSD, faster CPU, etc.