what does maximum actually mean on a cacti bandwidth graph?

[plossing]

Hi,

Can you explain how the graph data is calculated? Specifically, is "maximum" bandwidth the absolute peak data during a 5 minute average, or the maximum average?

For example, if my graph says 1mbps current, 5mbps avg, 47mbps maximum. Does that mean I hit a single peak of 47mbps or that I had a peak average of 47Mbps and that I could possiblly have hit 100Mbps?

Thank you,

[nowayza]

I'm ~new to Cacti and would also like to know the answer to the above question. Also, if you look at different time frames, would a max peak of 1Mbps in the last day be reported as max peak of 1Mbps for the last month graph?

I would also like to test throughput (maximum transfer rate between 2 points, up and down) to check and graph historical change in throughput. something like speedtest.net. I know iperf works well, but how would I log or export the data to RRD and graph it. I know the throughput information will be effected by current traffic when doing a test, but I was thinking of only scheduling the the test between 1am and 6am every 20 mins. any ideas how to do this ?

Thanks !!
J

[noname]

That depends what CF (consolidation function) is used for graph item in the graph template.



Normally Cacti uses "AVERAGE" for traffic template, so current/average/maximum values on graph are pulled(calculated) from series of averaged data.
"Average:" on graph means an average value of averages, "Maximum:" on graph means a maximum value of averages in the given time frame.

In addition, granularity of averaged data is determined by its RRA. (Data Sources -> RRAs)
e.g. "Daily" graph uses 5 minute averaged data, "Weekly" uses 30 minute averaged (and so on). It depends on 'steps' of RRA settings.

NOTICE: When 'Graph Item Type' is "GPRINT", the terms "AVERAGE/MIN/MAX/LAST" mean only for given time frame of the graph. They are slightly different from the RRA's.

For example, if my graph says 1mbps current, 5mbps avg, 47mbps maximum. Does that mean I hit a single peak of 47mbps or that I had a peak average of 47Mbps and that I could possiblly have hit 100Mbps?

Maybe the latter is.

Also, if you look at different time frames, would a max peak of 1Mbps in the last day be reported as max peak of 1Mbps for the last month graph?

Probably not.
Due to granularity of averaged data, a peak of monthly graph might be smaller than daily graph. Try using "MAX" CF instead of AVERAGE for that.

I would also like to test throughput (maximum transfer rate between 2 points, up and down) to check and graph historical change in throughput. something like speedtest.net. I know iperf works well, but how would I log or export the data to RRD and graph it. I know the throughput information will be effected by current traffic when doing a test, but I was thinking of only scheduling the the test between 1am and 6am every 20 mins. any ideas how to do this ?

Try to create Data Input Method so that Cacti can poll your data -or- create/update RRD file by yourself and import it as external RRD in order to make graph on Cacti.
- Data Input Methods
- Externally Updated RRDs

// Sorry my English