Values stored in rrd file does not match original values

classic Classic list List threaded Threaded
2 messages Options
Reply | Threaded
Open this post in threaded view
|

Values stored in rrd file does not match original values

pidou46
Hello,

I've build an application to monitor my heating system.

I keep in a log file the values I give to rrdtool by the update function.

When I proceed a fectch on a certain amount of time, the values doesn't match the values I've stored in the log file.

Here is an extract:

counter1.rrd monitor.log
t (s) dt (s) d conso Wh/min t (s) dt (s) imp d imp d conso Wh/min
                        1389896849,21 225061
1389896880 0,025 1389896910,31 61,0999999046 225065 4 2 80,43956044
1389896940 60 0,115 1389896971,41 61,1000001431 225088 23 11,5 100,2142857149
1389897000 60 0,498 1389897032,50 61,0899999142 225188 100 50 100,4390779364
1389897060 60 0,850 1389897093,60 61,0999999046 225297 109 54,5 64,0970437021
1389897120 60 1,025 1389897154,70 61,1000001431 225443 146 73 71,1910471599
1389897180 60 1,282 1389897215,80 61,0999999046 225613 170 85 66,3043478269
1389897240 60 1,311 1389897276,90 61,1000001431 225758 145 72,5 55,2812500015
1389897300 60 1,079 1389897338,00 61,0999999046 225871 113 56,5 52,3476237122
1389897360 60 0,818 1389897399,10 61,0999999046 225953 82 41 50,0921758235
1389897420 60 0,454 1389897460,20 61,1000001431 225958 5 2,5 5,5054151624
1389897480 60 0,038 1389897521,30 61,0999999046 225961 3 1,5 39,2142857145
1389897540 60 0,022 1389897582,40 61,1000001431 225965 4 2 92,6582278462
1389897600 60 0,033
                                                                64,8153617534
                7,551 452 0,0167059577

I hope it will be readable, of course I can deliver a pdf if needed.

The values given to update is "d conso Wh/min"  in monitor.log

The values fetched from rrd file is also "d conso Wh/min"

When reading the first to line it seems like I have a 100 factor but later it doesn't match.

The DEF is a COUNTER and I made an AVERAGE every minute.

I can also provide rrd file, and code extract from my python script.

An idea ?

Thanks
Reply | Threaded
Open this post in threaded view
|

Re: Values stored in rrd file does not match original values

Simon Hobson
I think what you are talking about is a well known issue due to normalisation. See the excellent tutorials at http://www.vandenbogaerdt.nl/rrdtool/ especially the one on "Rates, normalizing and consolidating"

_______________________________________________
rrd-users mailing list
[hidden email]
https://lists.oetiker.ch/cgi-bin/listinfo/rrd-users