RRD not being updated

[vmesquita]

Hello,

We are having an issue with the RRD used to store the bandwith usage of a Switch
The service check is:

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check_rrdtraf -f /var/lib/mrtg/192.168.50.100_10613.rrd -w 500.0,500.0 -c 800.0,800.0 -l M

wichi results :

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OK - Current BW in: 0Mbps Out: 0Mbps|in=0Mb/s;500.0;800.0 out=0Mb/s;500.0;800.0

However upon closer inspection, the file hasn't been updated since we migrated the Nagios Install:

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ls -ls /var/lib/mrtg/192.168.50.100_10613.rrd
104 -rwxrwxr-x 1 apache nagios 105320 Feb 21 18:51 /var/lib/mrtg/192.168.50.100_10613.rrd

In this migration, we installed a fresh CentOS 7, then Nagios and finally restored the backup. The previous server had CentOS 6.

Any ideas of what could be happening?

[scottwilkerson]

There are a couple possibilities, but being these are only used temporarily I would suggest renaming the file and let MRTG generate a new one

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mv /var/lib/mrtg/192.168.50.100_10613.rrd /var/lib/mrtg/192.168.50.100_10613.rrd~

then a new file should be generated within 5 minutes, and valid data should come to the check_rrdtraf plugin within 15 minutes

[vmesquita]

I did as suggested however the file was not created after half an hour, what could be happening?

[scottwilkerson]

Do you have any errors in

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tail -50 /var/log/cron |grep mrtg

related to mrtg?

If not lets run the following from the command line to see if there are any errors

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LANG=C LC_ALL=C /usr/bin/mrtg /etc/mrtg/mrtg.cfg --lock-file /var/lib/mrtg/mrtg_l --confcache-file /var/lib/mrtg/mrtg.ok --user=nagios --group=nagios

[vmesquita]

So apparently there's a lib missing:

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$ sudo tail -50 /var/log/cron |grep mrtg
Mar 26 15:45:01 sx591 CROND[85569]: (root) CMD (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)
$ LANG=C LC_ALL=C sudo /usr/bin/mrtg /etc/mrtg/mrtg.cfg --lock-file /var/lib/mrtg/mrtg_l --confcache-file /var/lib/mrtg/mrtg.ok --user=nagios --group=nagios
ERROR: could not find RRDs.pm. Use LibAdd: in mrtg.cfg to help mrtg find RRDs.pm

How can I fix this?

[tgriep]

The missing perl module can be installed by running this as root

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yum install rrdtool-perl

To test to see if MRTG can find the module, run the following command as root.

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LANG=C LC_ALL=C /usr/bin/mrtg /etc/mrtg/mrtg.cfg --lock-file /var/lib/mrtg/mrtg_l --confcache-file /var/lib/mrtg/mrtg.ok --user=nagios --group=nagios

If you do not see the "could not find RRDs.pm" message, let the system run for 20 minutes and see if the Bandwidth graphs start to populate.

[vmesquita]

Ok the files are being updated now, it seems that the issue have been fixed.

[tgriep]

That is good news, glad it worked.
I'll lock the post for you as solved but feel free to open a new post in the future for any new questions.