I have been developing frontend apps now for several years professionally and slowly feel the urge to learn how professionals set up their backends. I have decent knowledge in (relational) databases and I have set up my own experimental (!) amazon instances running apache/nginx with tomcat or nodejs. I however have no idea about scalability of server infrastructures and best practices of how to set these up. Therefore I am looking for some examples of different usecases regarding how server infrastructures should or can be set up in production environments. It doesn't matter too much which stack is used - I'm generally looking for some best practices for different kinds of scenarios.