A computing system is a set of hardware and the software components that control it. The software includes the operating system kernel which allocates resources and many modules that perform individual tasks, ranging from reading disk data to serving web pages.
An administrator needs to monitor these modules and applications to confirm that they are working correctly and to understand whether resources need to be reallocated (moving a user partition to a larger disk, providing a faster network, and so on).
Linux provides both interactive programs for examining the system's current performance and modules for logging performance over time.
This chapter describes the commands that monitor system activity and discusses logging techniques.
