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Method of calculating the bandwidth of NagiosXi graphs ?
Posted: Tue Mar 14, 2017 8:11 am
by Icarus
Hi,
I would like to know the method of calculating the bandwidth of NagiosXi graphs.
Does Nagios use the result of the OID Octets In and Out at a time T, where the flow information is retrieved directly in SNMP ?
Thanks
Re: Method of calculating the bandwidth of NagiosXi graphs ?
Posted: Tue Mar 14, 2017 3:43 pm
by mcapra
It's slightly more complicated than that (
MRTG is used to store the data, time is logged when the check is run), but that's the gist of it yes. The performance data of a typical bandwidth checks returns something like this:
Code: Select all
in=0Mb/s;50.00;80.00 out=0Mb/s;50.00;80.00
Where the value of in and out is the value of the respective OIDs, and the time is collected when the data is inserted into MRTG's back-end databases (sort of like a SQL
NOW()).
Re: Method of calculating the bandwidth of NagiosXi graphs ?
Posted: Mon Mar 20, 2017 9:22 am
by Icarus
Hi,
Are there incremented counters (number of packets or data quantities) that are distributed over time to obtain a bit rate, or the information received by snmp is directly a bit rate ?
Thanks
Re: Method of calculating the bandwidth of NagiosXi graphs ?
Posted: Mon Mar 20, 2017 4:17 pm
by mcapra
If I were looking at
Port 1 on host
192.168.5.42, this is roughly what gets ran at the CLI level:
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Using RRD file: /var/lib/mrtg/192.168.5.42_1.rrd
Input warning level(Mb/s): 50.00
Output warning level(Mb/s): 50.00
Input critical level (Mb/s): 80.00
Output critical level (Mb/s): 80.00
Fetching data with command: rrdtool fetch /var/lib/mrtg/192.168.5.42_1.rrd AVERAGE -s-10minutes | grep -vi "nan"
RRD File Data:
ds0 ds1
1490043900: 1.7957144235e+06 1.1482139460e+05
1490044200: 2.3002856646e+06 1.3019000204e+05
Raw Input Traffic Value (b/s): 18402285.316800
Raw Output Traffic Value (b/s): 1041520.016320
Decimal Input Traffic Value (b/s): 18402285
Decimal Output Traffic Value (b/s): 1041520
Traffic IN scalar: 1000000
Traffic OUT scalar: 1000000
OK - Current BW in: 18.40Mbps Out: 1.04Mbps|in=18.402285Mb/s;50.00;80.00 out=1.041520Mb/s;50.00;80.00
So it's basically taking an average of the last 10 minutes worth of traffic and seeing if that value is greater than the provided thresholds. The information received from SNMP is the direct bit rate at that very moment returned by the SNMP agent on the device, but for our wizard's checks we're averaging the last 10 minutes. Historically, this is a better metric to use since it more accurately represents legitimate traffic spikes rather than intermittent blips.
Re: Method of calculating the bandwidth of NagiosXi graphs ?
Posted: Tue Mar 21, 2017 6:08 am
by Icarus
Thanks for your anwser.
Re: Method of calculating the bandwidth of NagiosXi graphs ?
Posted: Tue Mar 21, 2017 9:23 am
by cdienger
Were there any more questions or are we okay locking this thread?
Re: Method of calculating the bandwidth of NagiosXi graphs ?
Posted: Tue Mar 21, 2017 11:46 am
by Icarus
Hi,
You can close this thread.
Thanks