Free Software

Back to resources.
Back to web site.

ntpstat.pl - MRTG Script to Display Clock Drift

5/13/2003

• Overview
• Downloading
• Implementation
• Sample Graphs
• Feedback / Questions

Overview

This script outputs data useful for generating an MRTG graph of NTP clock drift on an ongoing basis. It is useful to get a visual indication of hardware clock accuracy as well as whether your clock is being sync'd successfully.

As MRTG doesn't do negatives, positive drift is one color and negative another.

It's a very poorly written script, but seems to do a good job.

Downloading

The perl script can be found here. Refer to the next section for configuration information.

Implementation

Place the ntpstat.pl file in the directory where you normally run MRTG scripts from.

Add an mrtg.cfg entry like this:

# NTP Clock Offset
Target[ntpoff]: `/usr/local/mrtg-2/bin/ntpstat.pl`
XSize[ntpoff]: 360
YSize[ntpoff]: 75
Options[ntpoff]: gauge,growright,nopercent
Title[ntpoff]: NTP Clock Offset
MaxBytes[ntpoff]: 20480000
PageTop[ntpoff]: <H1>NTP Clock Offset</H1>
LegendO[ntpoff]: Negative Drift
LegendI[ntpoff]: Positive Drift
Legend2[ntpoff]: Negative Drift
Legend1[ntpoff]: Positive Drift
YLegend[ntpoff]: drift msecs
ShortLegend[ntpoff]: &nbsp;msecs
Colours[ntpoff]: DKBLUE#61A0DF,DKBLUE#0000DD,DARKGREEN#006600,VIOLET#FF00FF

Sample Graphs

---

`Monthly' Graph (2 Hour Average)

Max Positive Drift	36.0  msecs		Average Positive Drift	2.0  msecs		Current Positive Drift	26.0  msecs
Max Negative Drift	9.0  msecs		Average Negative Drift	2.0  msecs		Current Negative Drift	0.0  msecs

---

`Yearly' Graph (1 Day Average)

Max Positive Drift	16.0  msecs		Average Positive Drift	0.0  msecs		Current Positive Drift	5.0  msecs
Max Negative Drift	12.0  msecs		Average Negative Drift	1.0  msecs		Current Negative Drift	2.0  msecs

Feedback / Questions

There's not much to this script, but if you find it useful or have suggestions, please let us know.

E-Mail: contact@csma.biz.