[rrd-users] Measuring rain from weatherstation
linux at thehobsons.co.uk
Mon Dec 8 11:21:10 CET 2014
Alex van den Bogaerdt <alex at vandenbogaerdt.nl> wrote:
> As before: don't write to RRDtool unless the value tipped over to the next number. There won't be spikes. The amount of rain will be divided by the amount of seconds since the last update.
So use derive data type, write 0.5 (or any larger value that's accumulated) followed by 0 whenever the counter tips over ?
Guess we need to write 0 periodically to avoid getting long periods of unknown.
So we end up with :
if value > min
write T:value to rrd
writeT+1:0 to rrd
if timer > some_period
write T:0 to rrd
sleep for a bit
go back and do it all again
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