Nagios Support Forum

Posted: **Mon Oct 14, 2019 2:18 pm**

The data for Bandwidth graphs are collected using a application called MRTG and it that process is not retrieving the data for any reason, that could cause the issue in the graphs showing zero for the data.

Can you run the following commands as root and post the the /tmp/mrtg.txt file here so we can see if there are any errors, etc..?

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LANG=C LC_ALL=C /usr/bin/mrtg /etc/mrtg/mrtg.cfg -debug=cfg,base,log &> /tmp/mrtg.txt
LANG=C LC_ALL=C /usr/bin/mrtg &>> /tmp/mrtg.txt
LANG=C LC_ALL=C /usr/bin/mrtg /etc/mrtg/mrtg.cfg --lock-file /var/lib/mrtg/mrtg.lock --confcache-file /var/lib/mrtg/mrtg.ok --user=nagios --group=nagios &>> /tmp/mrtg.txt
{ time LANG=C LC_ALL=C /usr/bin/mrtg /etc/mrtg/mrtg.cfg 2>1 ; } 2>> /tmp/mrtg.txt

You could try this to see if it allows more MRTG forks to run so it can gather data.

Edit the /etc/mrtg/mrtg.cfg file and change this line from

Code: Select all

Forks: 4

to

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Forks: 16

Save the file and restart crond by running
service crond restart

See if this fixes the issue.

Posted: **Tue Oct 15, 2019 1:22 am**

Hi,

I've made the changes with Forks.
I''ll send the mrtg file to you through pm.

Posted: **Tue Oct 15, 2019 9:49 am**

Thanks for the mrtg file.

I feel increasing the Forks will solve the issue.

The MRTG process has to finish within 5 minutes to gather the data and the manual run that I had you do, took over 4 minutes.
If some of the devices you are polling take longer than normal, that could drive up the time to longer than 5 minutes and cause the zero bandwidth.

Take a look at the file and search for this message.
"did not eval into defined data"
Typically what that means is that the MRTG process is polling a device that is not responding to SNMP or that it does not exist.

If the device does not exist, remove the configuration file for it in the /etc/mrtg/conf.d folder and that will speed up the process as well.

Posted: **Wed Oct 16, 2019 12:25 am**

Thanks for the help.
Indeed, It seems that after the change to "Forks" the graphs have no gaps anymore.
I'll search for the not existing devices, too.
Thanks again..

Posted: **Wed Oct 16, 2019 8:23 am**

agpol07 wrote:Thanks for the help.
Indeed, It seems that after the change to "Forks" the graphs have no gaps anymore.
I'll search for the not existing devices, too.
Thanks again..

Great!

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