[mrtg] MRTG Max bits per second

Daniel J McDonald dan.mcdonald at austinenergy.com
Thu Nov 12 15:32:33 CET 2009

On Thu, 2009-11-12 at 13:29 +0000, Lee Todd wrote:
> I have mrtg configured with bit,  the graph shows in bits and the max, avg
> and current are all in bits.  We have a number of systems with gig links
> and even have a 6gig etherchannel into an ibm blade centre.  The max on any
> graph is 120.  Is this a limit

It is a limit of snmp version 1.  the 32 bit counter rolls over twice in
5 minutes at ~120mb/seconds

>  or a know issue and how do I fix it to show
> the real speed?

switch to snmp version 2c or snmp version 3.  These versions support 64
bit counters, which rollover about 1 four-millionth less frequently,
making those versions entirely appropriate for speeds up to about a
petabit per second.

snmpv2 can be set very simply.  Please read
http://oss.oetiker.ch/mrtg/doc/cfgmaker.en.html for complete
instructions.  snmpv3 is a little more challenging to configure, but
provides cryptographic integrity.  Once you get templates set up for
snmpv3, the operation is pretty straight-forward.

Daniel J McDonald, CCIE # 2495, CISSP # 78281, CNX

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