General Practice for a system administrator

Hello,

That's kind of a open ended question. As a system administrator, pretty much everything has to be monitored all the time. This would include memory consumption, CPU utilization, disk space (as you have already determined), log files need to be continuously monitored for intrusion and problems, and too many things to mention.

Since servers are running constantly, they also change constantly and therefore a server can have problems at a moments notice. There is no 100% optimal setting you can configure or a program you can install that would do all that for you.

System Administration is normally a learn as you go type of education. It just takes practice and you will have issues from time to time that simply need to be resolved. I've personally been doing this for over 20 years and I still have to constantly monitor all my servers.