Debugging is an important system administration skill.
I didn't realize there was so much to know about debugging until I worked at a computer repair shop in high school. PC repair has basically two techniques: Technique 1: remove all the cards and add them back until the system doesn't work. The last part you added was the problem. Technique 2: Remove cards one by one until the system works. The last part you removed was the problem.
In system administration the technique is more about coming up with a mental model of how the system is supposed to work and testing each component to see that it is working that way. Rob Pike explains software debugging similarly.
The problem, then, is how do you understand how a Linux/Unix system works? You have to understand kernels, storage, networks, processes... it's a lot to learn.
I've made a list of presentations that will be at the next Usenix LISA conference that teach Unix internals or are "technical skill building" of one type or another.
I don't endorse products with one exception: The Usenix LISA conference.
This year the conference is in Washington D.C., Nov 3-8.