Performance Tools

Just like looking at the temperature gauge in a car, you need to keep an eye on the performance metrics of your Linux systems. The tools are:

  • top
  • sar
  • vmstat
  • iostat
  • free

These tools can be run as a normal user. They all take advantage of the /proc filesystem to obtain their data. These performance tools are delivered with a few rpms. The procps rpm supplies top, free, and vmstat. The sysstat rpm provides sar and iostat.

The top command is a great interactive utility for monitoring performance. It provides a few summary lines of overall Linux performance, but reporting process information is where top shines. The process display can be customized extensively. You can add fields, sort the list of processes by different metrics, and even kill processes from top.

The sar utility offers the capability to monitor just about everything. It has over 15 separate reporting categories including CPU, disk, networking, process, swap, and more.

The vmstat command reports extensive information about memory and swap usage. It also reports CPU and a bit of I/O information. As you might guess, iostat reports storage input/output (I/O) statistics.