How to identify a process that gives a strong CPU load and the system as a whole?

Question

System administration

Earlier, I sinned on the web server and thought that it was some kind of bot loading the server at a certain time (and by 6 am Moscow time), but after a month of observation, I came to the conclusion that this is not a web, something else.
Question: how to determine the load source by regular means?

Answer 1

top sorts processes based on the resources they consume.
Then either keep it constantly running, or write scripts:
- Using Cron, we look at the current download. If it exceeded the threshold, collect the system state
( ps ; top etc.).
Let's take a look at the logs...