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    <center><h1>NET-SNMP Tutorial -- MRTG</h1></center>
    <hr>
    <p> 
    This page will present a few ideas of what you can monitor on your
    hosts with the net-snmp using the <a href="http://www.mrtg.org">mrtg</a>
    utility.
    <p>
    This is <i>not</i> an MRTG tutorial, and it is <i>not</i>
    going to talk about monitoring network traffic.
    <p>
    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.
    <p>
    <h2>Monitoring CPU load</h2>
    <p>
    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.
    <a name="cpu.html">
    <h3>User vs Idle CPU usage</h3>
    An example of such a graph is <a href="kontor.cpu.html">here</a>.
    <p>
    The corresponding MRTG configuration is
    <pre>
    LoadMIBs: /usr/local/share/snmp/mibs/UCD-SNMP-MIB.txt

    Target[kontor.cpu]:ssCpuRawUser.0&amp;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]: &lt;H1>User CPU Load %&lt;/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]: &nbsp;User
    LegendO[kontor.cpu]: &nbsp;Idle
    Options[kontor.cpu]: growright,nopercent
    </pre>
    <a name="usrsys.html">
    <h3>User vs System CPU usage</h3>
    An example of such a graph is <a href="kontor.usrsys.html">here</a>.
    <p>
    The corresponding MRTG configuration is
    <pre>
    LoadMIBs: /usr/local/share/snmp/mibs/UCD-SNMP-MIB.txt

    Target[kontor.usrsys]:ssCpuRawUser.0&amp;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]: &lt;H1>CPU (user and system) Load %&lt;/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]: &nbsp;User
    LegendO[kontor.usrsys]: &nbsp;System
    Options[kontor.usrsys]: growright,nopercent
    </pre>
    <a name="cpusum.html">
    <h3>Active CPU usage</h3>
    An example of such a graph is <a href="kontor.cpusum.html">here</a>.
    This example sums User, System and Nice and plots it as a single value.
    <p>
    The corresponding MRTG configuration is
    <pre>
    LoadMIBs: /usr/local/share/snmp/mibs/UCD-SNMP-MIB.txt

    Target[kontor.cpusum]:ssCpuRawUser.0&amp;ssCpuRawUser.0:public@10.10.11.2 + ssCpuRawSystem.0&amp;ssCpuRawSystem.0:public@10.10.11.2 + ssCpuRawNice.0&amp;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]: &lt;H1>Active CPU Load %&lt;/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]: &nbsp;Active
    LegendO[kontor.cpusum]:
    Options[kontor.cpusum]: growright,nopercent
    </pre>
    <h2>Monitoring DISK space</h2>
    <p>
    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
    <p>
    On the system I used for these examples, I have the following disks:
    <pre>
    $ 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
    </pre>
    and I have put the following lines into snmpd.conf:
    <pre>
    disk	/	100000
    disk	/usr	100000
    disk	/space	100000
    </pre>
    <a name="root.html">
    <h3>Monitoring from dskTable</h3>
    I used the direct percentage of disk full for the root and /usr
    partitions in <a href="kontor.root.html">this example</a>
    It plot the usage of the root and the /usr partitions in one graph.
    <pre>
    LoadMIBs: /usr/local/share/snmp/mibs/UCD-SNMP-MIB.txt

    Target[kontor.root]:dskPercent.1&amp;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]: &lt;H1>DISK / and /usr Usage %&lt;/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]: &nbsp;Root disk
    LegendO[kontor.root]: &nbsp;/usr disk
    Options[kontor.root]: growright,gauge,nopercent
    </pre>
    <a name="kontor.hrroot">
    <h3>Monitoring from hrStorageTable</h3>
    Use of hrStorageTable requires no preceding configuration, as in
    <a href="kontor.hrroot.html">this example</a>
    It plot the partition size as one value, and the used space as another.
    <b>Note:</b>the values returned here are in units of hrStorageUnits, which,
    dependent on the file system type, may or may not be 1K.
    <pre>
    LoadMIBs: /usr/local/share/snmp/mibs/HOST-RESOURCES-MIB.txt

    Target[kontor.hrroot]:hrStorageSize.1&amp;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]: &lt;H1>DISK / Usage&lt;/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]: &nbsp;Root disk size
    LegendO[kontor.hrroot]: &nbsp;Root disk usage
    Options[kontor.hrroot]: growright,gauge,nopercent
    </pre>
    <p>
    Two further examples that have been offered:
    <h3>Monitoring TCP connections</h3>
    <p>
    <pre>
    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]: &nbsp;Connections: 
    LegendO[tcpopen]: 
    Legend1[tcpopen]: Open TCP connections 
    </pre>
    <p>
    and
    <h3>Monitoring Free Memory</h3>
    <p>
    <pre>
    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]: &nbsp;Free Memory: 
    LegendO[freemem]: 
    Legend1[freemem]: Free memory, not including swap, in bytes
    </pre>
    <a href="mrtgindex.html">The complete picture</a>
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