Nmon – linux monitoring tools

nmon is a beutiful tool to monitor linux system performance. It works on Linux, IBM AIX Unix, Power, x86, amd64 and ARM based system such as Raspberry Pi. The nmon command displays and records local system information. The command can run either in interactive or recording mode.
Nmon is a short for Nigel’s performance Monitor. This tool is used to monitor resources on Linux, Power, x86, x86_64, Mainframe and ARM (Raspberry Pi). There are two mode available of nmon.

1. Online Mode, which used to real-time monitoring.
2. Capture Mode, which the output will saved to a CSV file for later processing


  • There are two modes available:
    1. In Online Mode it uses curses for efficient screen handling, which updates the terminal frequently for real-time monitoring.
    2. In Capture Mode, the data is saved to a file in CSV format for later processing and graphing. The file also includes important configuration details that are useful for recommending tuning.
    • nmon concentrates on performance information for the performance tuner and in a concise layout to aid understanding. This includes: CPU, memory, disks, adapters, networks, NFS, Kernel statistics, File-systems, Workload Manger (AIX), Workload Partitions (AIX) and Top Processes.
    • nmon includes support for older AIX releases, Linux running on x86, POWER and Mainframe platforms.

    More information about nmon

    Install nmon on Ubuntu 12.04/12.10/13.04/13.10/14.04 and Linux Mint 13/14/15/16

    To install nmon on Ubuntu 12.04/12.10/13.04/13.10/14.04 and Linux Mint 12/13/14/15/16 enter following command:

    # sudo apt-get install nmon

    Install nmon on RHEL/CentOS 5.x/6.x and Fedora 16/17/18/19/20

    First, install rpm forge repository and enter folloving command:

    # yum install nmon

    How do I use nmon?

    Simply type the following command:

    # nmon
    nmon startup screen
    nmon startup screen

    nmon keyboard shortcuts

    • q – To stop and exit nmon.
    • h – To see quick help (hint) screen and press h again to remove the hints.
    • Use the following command to turn on or off stats:
    • c – See cpu stats.
    • m – See memory stats.
    • d – See disk stats.
    • k – See kernel stats.
    • n – See network stats.
    • N – See NFS stats.
    • j – See file system stats.
    • t – See top process.
    • V – See virtual memory stats.
    • . – See only busy disks/procs.
    • v – Verbose mode (display as Ok/warning/danger on screen).

    Check CPU by processor

    If you like to collect CPU performance statistics press “c” key on your keyboard. After hitting the “c”  see example screen:

    nmon CPU Utilisation
    nmon CPU Utilisation

    If you see information of another system resources press another keys:

    • m = Memory
    • j = Filesystems
    • d = Disks
    • n = Network
    • V = Virtual Memory
    • r = Resource
    • N = NFS
    • k = kernel
    • t = Top-processes
    • . = only busy disks/procs

    Show Memory stats

    Use the ‘m‘ key to get Memory Stats information:

    nmon memory stats
    nmon memory stats

    Check Disk I/O stats

    To see Disk I/O information press “d” key on your keyboard

    nmon disk I/O
    nmon disk I/O

    Check Network statistics

    To see network statistics press “n” key on your keyboard

    nmon Network I/O
    nmon Network I/O

    Nmon System information

    Use the ‘r‘ key to show System information:

    Nmon System information
    Nmon System information

    If you are having any suggestion, let me know via our comment section.

    See also: Collectl – Monitoring system resources


    Leave a Reply

    Your email address will not be published. Required fields are marked *


    This site uses Akismet to reduce spam. Learn how your comment data is processed.

    Back to top button