[rrd-users] water usage

Rick Dicaire kritek at gmail.com
Thu Jul 22 20:32:48 CEST 2010

Hi folks, I'm trying to log water usage based on once daily data
input. I've tried DS types of COUNTER and GAUGE, and the graph image
doesn't appear to reflect each days usage. Here's how I'm creating the

rrdtool graph 'water.png' --title 'Water Usage' --vertical-label 'Gallons' \
--start end-1w \
'DEF:av=/backup/mrtg-2/mrtg/rrd/water.rrd:gallons:AVERAGE' \
'DEF:mi=/backup/mrtg-2/mrtg/rrd/water.rrd:gallons:MIN' \
'DEF:ma=/backup/mrtg-2/mrtg/rrd/water.rrd:gallons:MAX' \
'DEF:la=/backup/mrtg-2/mrtg/rrd/water.rrd:gallons:LAST' \
'LINE1:av#0000FF' \
'LINE1:mi#00FF00' \
'LINE1:ma#006600' \

Using either of the above DS types produces a steadily upward
'stepped' graph. So it appears I need to get the difference between
the LAST input and the one previous input, and graph that. How can
this be done?


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