Troubleshooting resource issues

I don't know about others, but it seems that a majority of my time troubleshooting servers usually comes down to pinpointing resource issues. By resources, I'm referring to CPU, memory, disk, input/output, and so on. Generally, issues come down to a user storing too many large files, a process going haywire that consumes a large amount of CPU, or a server running out of memory. In this section, we'll go through some of the common things you're likely to run into while administering Ubuntu servers.

First, let's revisit topics related to storage. In Chapter 3, Managing Storage Volumes, we have gone over concepts related to this already, and many of those concepts also apply to troubleshooting as well. Therefore, I won't spend too much time on those concepts here, but it's worth a refresher in regards to troubleshooting storage issues. First, whenever you have users that are complaining about being unable to write new files...