How To

Summary

This article is the original "Developer Works" web page for the nmon performance tool for AIX and Linux with links updated

Objective

Steps

nmon for AIX Performance Monitoring

STOP PRESS: 27 July 2009 - nmon for Linux released to open source

nmon for Linux released to open source under GPL - it was an internal project at IBM for many years.
The source code and further information are available at Sourceforge and in particular at the new nmon for Linux wiki at http://nmon.sourceforge.net
This means that you can compile nmon for Linux for your specific Linux flavour and help improve it further.

STOP PRESS: 21 Nov 2008 - nmon made part of AIX

nmon for AIX included with AIX from 5.3 TL09, AIX 6.1 TL02, and Virtual I/O Server (VIOS) 2.1 . It is installed by default.
The nmon functionality is integrated within the topas command (as both tools use the same data source), which can be started in topas mode or nmon mode (just type "nmon"). You can flip between the two modes online by typing "~". You can also start nmon to capture to a file with the regular nmon options (nmon -f ... ). This tool gives you the best of both worlds - one tool to watch the CEC/whole machine view of all your logical partitions (topas -C) and the same tool to drill down into the details of your AIX system in nmon style.
This new AIX version is called topas_nmon and is fully supported by AIX Support so use your regular support channel. It contains the same feature set as "classic" nmon version 12e. The classic version is still supported on the Performance Tool forum and should be used for all older AIX releases but is now "functionally stabilized" that is new features go into the topas_nmon version. New features planned for topas_nmon come from new advanced features in the next AIX releases and new data that is only available on those new AIX releases, so these are to be added to the topas_nmon version within AIX. Note: as a side effect, there is no delay in topas_nmon catching up with AIX features.

Sample Online Output - when displayed on screen in real-time

Briefly - What is nmon?

nmon is short for Nigel's Monitor. Nigel Griffiths in the creator and developer for the first two decades years.
This free tool gives you a huge amount of important performance information in one go.

It can output the data in a number of ways
On-screen (console, telnet, VNC, putty or X Windows) that uses curses for low CPU impact, which is updated once every two seconds. You hit single characters on your keyboard to enable or disable the various sorts of data.
Save the data to a comma-separated file for analysis and longer-term data capture.
nmon is a single binary for each operating system, so installing is as easy as getting the file in your $PATH.
Why use five or six tools when one free tool can give you everything you need!!

Warnings and Notices

Original nmon classic - No warranty is given or implied. Feel free to use these nmon files any way you like but it is at your own risk.
topas_nmon comes with modern AIX operating system versions is included in the regular AIX Support and PMRs.
nmon for Linux is Open Source the developer helps you and answer questions.
Apart from writing to the output file, nmon does not update or change anything on your machine or operating system.

What sort of Performance Data?

CPU utilization
Memory use
Kernel statistics and run queue
Disks I/O rates, transfers, and read/write ratios
File system size and free space
Disk adapters
Network I/O rates, transfers, and read/write ratios
Paging space and paging rates
Machine details, CPU, and OS specification
Top processors
User-defined disk groups
Asynchronous I/O = AIX only
Workload Manager = AIX only
ESS and other disk subsystem = AIX only
Dynamic LPAR changes = AIX and Linux (on POWER hardware)

Updates

The nmon for AIX tool is updated with each new operating system Technology Level release and fixes released with service packs.
Twitter - We no longer operate the nmon email list - if you want to keep up to date and in touch with changes then this is done via Twitter, follow "mr_nmon" for nmon, performance and system admin information. Thanks, Nigel Griffiths.

nmon Documentation and Information

nmon for AIX comes with AIX
nmon for Linux can be found in some Distro repositories or downloads from http://nmon.sourceforge.net
nmon Analyser Excel Spread-sheet Download - http://nmon.sourceforge.net and the nmon-Analyser page
Example C source code of how nmon gets its data from AIX -Roll Your Own AIX Performance Monitor via Code Samples
Learn nmon basics from the YouTube movies from the https://www.youtube.com/user/nigelargriffiths

Document Location

Worldwide

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Tips

Original nmon web page