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Control over MRTG databases

Posted: Tue Oct 21, 2025 3:10 pm
by juergen
Hello,

We are using Nagios XI 2024R1.3.3, and need to run MRTG at least once a minute (and keep the results).

I have set up a few interfaces through the Network Switch / Router Configuration Wizard, but we seem to get samples only every 5 minutes.

I have edited /etc/cron.d/mrtg to run every minute, but it looks like the RRD files set up by the wizard are configured to only keep samples every 5 minutes, no matter how often I feed them.

Is there a way from within the web interface to adjust the characteristics of the RRD files (sample frequency and retention)? If not, can I remove the files and re-create them with the characteristics I need?

Thanks.

Re: Control over MRTG databases

Posted: Thu Oct 23, 2025 4:40 pm
by kfanselow
Hi juergen,

Thank you for your patience and that's an interesting question. Unfortunately we do not have a way to adjust the RRD files via the interface and our implementation of MRTG is intended to work with the 5 minute cadence. It sounds like you've updated the call in cron correctly but you may want to review the MRTG documentation on adjusting the step via the config file. Toby's documentation probably has better guidance on how to do it and what is possible with the way the rrd files are being created and updated within MTRG itself.

https://oss.oetiker.ch/mrtg/doc/index.en.html

As always we recommend that you make sure you have good backups and that you test your changes on a test server prior to making any changes in production. Our license specifically allows for 3 separate activations for this very reason. One for production, one for testing, and one for high availability.

Nagios License Entitlements:
https://support.nagios.com/kb/article.php?id=145

Thanks and Kind Regards,
Keith

Re: Control over MRTG databases

Posted: Fri Oct 24, 2025 3:26 pm
by juergen
Thanks for letting me know.