problem with average in cacti

[jeff705]

Hello,

I have a problem with the average in the graphs cacti ...
I put screenshots and graphics configuration.

The average graph "traffic" isn't ok, it is not possible ...
The total value of Out and In is incorrect as it seems.

I also have a chart that calculates the RTT. When I take the instantaneous values, it's ok!
But once you take the average, nothing it's ok! The values given by cacti are impossible ...

My questions are:

On what basis are cacti to calculate the average? the values of the graphics displayed? The values recorded? or the values recorded after sampling?

Is sampling may be involved?
(I put a screen shot of my setup)

Compared to the chart "Traffic", you have a template that you are sure of the values returned by cacti?

For sampling, how should I configure it?


Thank you in advance for your help!

[jeff705]

here is the rest of the screen shot and also graph the rtt and the configuration of the sampling

[noname]

To mention this part only,

On what basis are cacti to calculate the average? the values of the graphics displayed? The values recorded? or the values recorded after sampling?

That's depend on RRDtool feature, and these pages may help..
http://oss.oetiker.ch/rrdtool/tut/rrd-beginners.en.html
http://www.vandenbogaerdt.nl/rrdtool/process.php
(keyword: PDP, CDP, STEP)

I understand 'AVERAGE' as the value calculated from actual data recorded in a period of given graph (=timespan settings), not from sampled data.
For example, Daily graph has 288 data points (=86400/300), Weekly has 2016 (=604800/300), ..
You can verify this by exporting graph to CSV and calculating average from inside data.

(If I'm misleading, please point out..)



Memo: Actual number of data in CSV may be less than mentioned above. (Daily has 287, Weekly has 2010, ...)
I think that two datasets(*) with their resolution are needed to decide the first point in graph (calculating the difference like as COUNTER), so first dataset was consumed.

(*) For Weekly, 1 dataset = 30 minutes = 6 data).

// Sorry my REALLY BAD English..

[noname]

Oh, sorry, I've misguided.

For example, Daily graph has 288 data points (=86400/300), Weekly has 2016 (=604800/300), ..
You can verify this by exporting graph to CSV and calculating average from inside data.

That's the case of my cacti. :oops:
In my cacti, I modified default RRA settings as follows:

Code: Select all

Name                        Steps   Rows
Daily   (5 Minute Average)    1    115200 (=400 days)
Weekly  (30 Minute Average)   6     19200 (=400 days)
Monthly (2 Hour Average)     24      4800 (=400 days)

When exporting from graph [by lib/rrd.php], cacti seems to select appropriate resolution (= most detailed one among RRAs which has actual data of given resolution?) automatically.
So I saw 2000+ data which exported from Weekly graph.

[levi912]

i have the same problem, have you resolved it?