@Joe,
My primary point was, I find that when you try to cram everything on a single “small” VPS, you are not giving everything enough resources to run “properly”. I see people placing full stacks on 1GB or 2GB systems, then they load the same system with a bunch of busy (or unoptimized) WordPress sites and start to see issues with overall performance. A quick look at “htop” shows they’re spiking their resources regularly and they wonder why services start to shutdown… 
*** I’ve also noticed lately MySQL tends to chew through a ton of CPU/Memory when not setup correctly or you start loading lots of database heavy scripts. ***