[rrd-users] Managing unknown values
fbusse at gmx.de
Mon Aug 9 09:59:41 CEST 2010
I hope this is not too much of an FAQ:
I'm using rrdtool to graph the temperature readout of a sensor.
The step of the DB is 60 seconds (to get a high resolution), the cronjob
runs every minute as well.
RRA looks like this: RRA:temp:GAUGE:600:U:U RRA:AVERAGE:0.5:1:2880
Unfortunatly, that sensors is sometimes slow to respond and returns no
value, in which case my scripts returns "U".
This is an example of what is written with rrdupdate:
After this, the RRD itself contains this
That creates an "ugly" spike in the graph.
What is the recommend way to make sure that an unkown value does not
have such a huge impact?
Basically I'd like values written to the RRD as unknown to be ignored or
interpolated from valid data before and after the unknown readout.
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