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% /space
and 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 bytes
The complete picture
Last modified: Wednesday, 01-Aug-2018 04:41:28 UTC
For questions regarding web content and site functionality, please write to the net-snmp-users mail list.