Monitoring Linux performance and looking at Linux information.

In my work, I was looking into why a web server was performing poorly. I decided after finding the issue was with a dying disk, that I should post about the various tools Linux has to offer, and what they do. Awareness is the primary key. If you want learn more about each tool, you can run a man <command> to go into the details. Playing with the commands over time is the best way to retain the knowledge.

CPU usage:

  1. sar
  2. top
  3. Memory utilization:
  4. free -h
  5. top

Disk performance and IO

  1. iostat
  2. sar

Disk usage

  1. df -h
  2. du <directory> -cks -h I write it that way as a mnemonic of…”du cks” with a -h(human readable) flag.


  1. ss -ptuna | grep -i listen
  2. lsof -P – I -n | grep Listen
  3. tcpdump

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