Author: Matt Aurand

A runlevel is one of the modes that a Unix-based, dedicated server or a VPS server OS will run on. Each runlevel has a certain number of services stopped or started, giving the user control over the behavior of the machine. Conventionally, seven runlevels exist, numbered from zero to six.

When reviewing the resources utilized by your server, there are a plethora of tools at your disposal. The sar command is a powerful Linux command line utility that can be used to review a server’s resource usage.