This page will present a few ideas of what you can monitor on your hosts with the net-snmp using the mrtg utility.
This is not an MRTG tutorial, and it is not going to talk about monitoring network traffic.
Note, that these examples uses values that are only available from net-snmp-4.2 or above and that the LoadMIBs mrtg directive requires mrtg-2.8.0.
There are several ways to try to monitor CPU usage, because the system
maintains several CPU counters: Idle, System, User, Nice.
As MRTG does not allow you to graph more than two values at a time,
it is possible to select any two values ang graoh aginst each other,
but it it also possible to compute a combined value.
User vs Idle CPU usage
An example of such a graph is here.
The corresponding MRTG configuration is
LoadMIBs: /usr/local/share/snmp/mibs/UCD-SNMP-MIB.txt Target[kontor.cpu]:ssCpuRawUser.0&ssCpuRawIdle.0:public@10.10.11.2 RouterUptime[kontor.cpu]: public@10.10.11.2 MaxBytes[kontor.cpu]: 100 Title[kontor.cpu]: CPU LOAD PageTop[kontor.cpu]: <H1>User CPU Load %</H1> Unscaled[kontor.cpu]: ymwd ShortLegend[kontor.cpu]: % YLegend[kontor.cpu]: CPU Utilization Legend1[kontor.cpu]: User CPU in % (Load) Legend2[kontor.cpu]: Idle CPU in % (Load) Legend3[kontor.cpu]: Legend4[kontor.cpu]: LegendI[kontor.cpu]: User LegendO[kontor.cpu]: Idle Options[kontor.cpu]: growright,nopercent
The corresponding MRTG configuration is
LoadMIBs: /usr/local/share/snmp/mibs/UCD-SNMP-MIB.txt Target[kontor.usrsys]:ssCpuRawUser.0&ssCpuRawSystem.0:public@10.10.11.2 RouterUptime[kontor.usrsys]: public@10.10.11.2 MaxBytes[kontor.usrsys]: 100 Title[kontor.usrsys]: CPU LOAD PageTop[kontor.usrsys]: <H1>CPU (user and system) Load %</H1> Unscaled[kontor.usrsys]: ymwd ShortLegend[kontor.usrsys]: % YLegend[kontor.usrsys]: CPU Utilization Legend1[kontor.usrsys]: User CPU in % (Load) Legend2[kontor.usrsys]: System CPU in % (Load) Legend3[kontor.usrsys]: Legend4[kontor.usrsys]: LegendI[kontor.usrsys]: User LegendO[kontor.usrsys]: System Options[kontor.usrsys]: growright,nopercent
The corresponding MRTG configuration is
LoadMIBs: /usr/local/share/snmp/mibs/UCD-SNMP-MIB.txt Target[kontor.cpusum]:ssCpuRawUser.0&ssCpuRawUser.0:public@10.10.11.2 + ssCpuRawSystem.0&ssCpuRawSystem.0:public@10.10.11.2 + ssCpuRawNice.0&ssCpuRawNice.0:public@10.10.11.2 RouterUptime[kontor.cpusum]: public@10.10.11.2 MaxBytes[kontor.cpusum]: 100 Title[kontor.cpusum]: CPU LOAD PageTop[kontor.cpusum]: <H1>Active CPU Load %</H1> Unscaled[kontor.cpusum]: ymwd ShortLegend[kontor.cpusum]: % YLegend[kontor.cpusum]: CPU Utilization Legend1[kontor.cpusum]: Active CPU in % (Load) Legend2[kontor.cpusum]: Legend3[kontor.cpusum]: Legend4[kontor.cpusum]: LegendI[kontor.cpusum]: Active LegendO[kontor.cpusum]: Options[kontor.cpusum]: growright,nopercent
There are two tables that can be used when monitoring disk space, UCD-SNMP-MIB:dskTable and HOST-RESOURCES-MIB:hrStorageTable. There are two noticeable differences bwtween these tables: UCD-SNMP-MIB:dskTable requires a configuration directive in snmpd.conf, but it also gives a direct measure of the percentage of free space
On the system I used for these examples, I have the following disks:
$ df Filesystem Size Used Avail Use% Mounted on /dev/hda6 289M 56M 218M 21% / /dev/hda1 7.3G 3.2G 4.1G 44% /mnt/windows /dev/hda7 1.7G 1.2G 429M 74% /usr /dev/hdc1 19G 6.7G 11G 37% /spaceand I have put the following lines into snmpd.conf:
disk / 100000 disk /usr 100000 disk /space 100000
LoadMIBs: /usr/local/share/snmp/mibs/UCD-SNMP-MIB.txt Target[kontor.root]:dskPercent.1&dskPercent.2:public@10.10.11.2 RouterUptime[kontor.root]: public@10.10.11.2 MaxBytes[kontor.root]: 100 Title[kontor.root]: DISK USAGE PageTop[kontor.root]: <H1>DISK / and /usr Usage %</H1> Unscaled[kontor.root]: ymwd ShortLegend[kontor.root]: % YLegend[kontor.root]: DISK Utilization Legend1[kontor.root]: Root disk Legend2[kontor.root]: /usr disk Legend3[kontor.root]: Legend4[kontor.root]: LegendI[kontor.root]: Root disk LegendO[kontor.root]: /usr disk Options[kontor.root]: growright,gauge,nopercent
LoadMIBs: /usr/local/share/snmp/mibs/HOST-RESOURCES-MIB.txt Target[kontor.hrroot]:hrStorageSize.1&hrStorageUsed.1:public@10.10.11.2 RouterUptime[kontor.hrroot]: public@10.10.11.2 MaxBytes[kontor.hrroot]: 300000 Title[kontor.hrroot]: DISK / USAGE PageTop[kontor.hrroot]: <H1>DISK / Usage</H1> ShortLegend[kontor.hrroot]: B kMG[kontor.hrroot]: k,M,G,T,P kilo[kontor.hrroot]: 1024 YLegend[kontor.hrroot]: DISK / Utilization Legend1[kontor.hrroot]: Root disk size Legend2[kontor.hrroot]: Root disk usage Legend3[kontor.hrroot]: Legend4[kontor.hrroot]: LegendI[kontor.hrroot]: Root disk size LegendO[kontor.hrroot]: Root disk usage Options[kontor.hrroot]: growright,gauge,nopercent
Two further examples that have been offered:
Target[tcpopen]: .1.3.6.1.2.1.6.9.0&.1.3.6.1.2.1.6.9.0:public@localhost Options[tcpopen]: nopercent,growright,gauge,noinfo Title[tcpopen]: Open TCP connections PageTop[tcpopen]: Open TCP connections MaxBytes[tcpopen]: 1000000 YLegend[tcpopen]: # conns ShortLegend[tcpopen]: connections LegendI[tcpopen]: Connections: LegendO[tcpopen]: Legend1[tcpopen]: Open TCP connections
and
Target[freemem]: .1.3.6.1.4.1.2021.4.11.0&.1.3.6.1.4.1.2021.4.11.0:public@localhost Options[freemem]: nopercent,growright,gauge,noinfo Title[freemem]: Free Memory PageTop[freemem]: Free Memory MaxBytes[freemem]: 1000000 kMG[freemem]: k,M,G,T,P,X YLegend[freemem]: bytes ShortLegend[freemem]: bytes LegendI[freemem]: Free Memory: LegendO[freemem]: Legend1[freemem]: Free memory, not including swap, in bytesThe complete picture
Last modified: Wednesday, 01-Aug-2018 04:41:28 UTC
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