Nagios Support Forum

The root account on our nagiosxi server is receiving e-mails that indicate that snmp queries are failing for hosts that have been removed from the nagios configuration, and do not exist among the nagios host files in the directory structure of the server. The subject of the e-mails indicates the following location for the command / configuration file that directs the snmp queries to be launched. The command is /usr/bin/mrtg and the configuration file is /etc/mrtg/mrtg.cfg. Examination of the file /etc/mrtg/mrtg.cfg show lines like the following:

#### ADDED BY NAGIOSXI (USER: nagiosadmin, DATE: 2010-01-29 20:07:35) ####

Here's an example of a "configuration" in the file for a device that no longer exists:

#### ADDED BY NAGIOSXI (USER: nagiosadmin, DATE: 2010-01-29 20:27:46) ####
# Created by
# /usr/bin/cfgmaker --noreversedns [email protected]


### Global Config Options

# for UNIX
# WorkDir: /home/http/mrtg

# or for NT
# WorkDir: c:\mrtgdata

### Global Defaults

# to get bits instead of bytes and graphs growing to the right
# Options[_]: growright, bits

EnableIPv6: no

######################################################################
# System: Oc************
# Description: **************, Version: 14.02.00.E, Date: Fri Jan 12 11:10:57 2007
# Contact:
# Location:
######################################################################


### Interface 1 >> Descr: 'eth-0/1:-MAC:PQIII-TSEC1-PHY:ICS1893BF-v4.2' | Name: 'eth 0/1' | Ip: '192.168.6.1' | Eth: '30-78-30-30-61-30-63-38-32-34-63-65-37-36' ###

Target[192.168.206.2_1]: 1:[email protected]:
SetEnv[192.168.206.2_1]: MRTG_INT_IP="192.168.6.1" MRTG_INT_DESCR="eth-0/1:-MAC:PQIII-TSEC1-PHY:ICS1893BF-v4.2"
MaxBytes[192.168.206.2_1]: 12500000
Title[192.168.206.2_1]: Traffic Analysis for 1 -- Oc*****
PageTop[192.168.206.2_1]: <h1>Traffic Analysis for 1 -- Oc*********</h1>
<div id="sysdetails">
<table>
<tr>
<td>System:</td>
<td>Ocala3430 in </td>
</tr>
<tr>
<td>Maintainer:</td>
<td></td>
</tr>
<tr>
<td>Description:</td>
<td>eth-0/1:-MAC:PQIII-TSEC1-PHY:ICS1893BF-v4.2 </td>
</tr>
<tr>
<td>ifType:</td>
<td>ethernetCsmacd (6)</td>
</tr>
<tr>
<td>ifName:</td>
<td>eth 0/1</td>
</tr>
<tr>
<td>Max Speed:</td>
<td>12.5 MBytes/s</td>
</tr>
<tr>
<td>Ip:</td>
<td>192.168.6.1 ()</td>
</tr>
</table>
</div>


My quandary is whether there is a way to make nagios remove or comment out all of the no longer relevant parts of the /etc/mrtg/mrtg.cfg, or is this something that needs to be done manually in the mrtg.cfg file. As a follow-up I'd ask, could the failed SNMP queries that are being made to non-existent hosts be a factor in degrading performance on the server?

If a large number of interfaces are being checked by MRTG and are timing out it could have a impact on your servers performance. At the current time removing hosts/services which have been configured in the mrtg.cfg file does not remove them from that file so they must be manually removed. We have been working towards a number of improvements to the way Nagios XI integrates with MRTG "Third party software" and I believe this is one of those changes that is being worked on.