# [rrd-users] Re: Gauge understanding problem or error ?

Christian Volkmann CVolkmann at orga-systems.com
Fri Aug 19 15:43:42 MEST 2005

```Hi Alex,

first of all _thank you very much_ that you take care of questions in such
a patient way !

So the following works like expected. May be it can be "prepared" in a proper
way and added to the samples after a review and correction ?

Best regards,

Christian

PS: Solved for me. But not complete "satisfied" by the design.
May be I need to redesign my mind a little to understand ;-)

==========================================================
Situation:
You want to record and view a graph about maximum  temperature.
You get samples in the rate of 60 seconds.

consolidation of the data. These different results might confuse a
beginners expectation. See at the tutorial the section "Data Resampling".

The following should work:
#########################
# sample
# creation of the database

STEP=1           # record one second steps
STEPSFORCDP=60   # use 60 steps to build a consolidated data point
let DURATION="24*60*60"  # one day with 24 hours which have 60 minutes which have 60 seconds
let TORECORD="\$DURATION/STEPSFORCDP/STEP"
MINTEMP=0
MAXTEMP=100
MINDATARATE=60
START=`date -d "now -24hour" +%s`  # start database for now-24 hours

rrdtool create test.rrd --start \$START -s \$STEP \
DS:TEMPERATUR:GAUGE:\$MINDATARATE:\$MINTEMP:\$MAXTEMP \
RRA:LAST:0:\$STEPSFORCDP:\$TORECORD

# record your values every 60 seconds:
# endless loop...
while true
do
rrdtool update test.rrd N:\$TEMP
sleep 60
done

# use the following command to show the graph of the last 24 hours:
SHOWSTART=`date -d "now -24hour" +%s`
SHOWEND=`date +%s`

rrdtool graph test.gif -t "Temperature of the last 24 hours" --start \$SHOWSTART --end \$SHOWEND \
DEF:value=test.rrd:TEMPERATUR:LAST \
LINE1:value#00FF00:Temperatur

################################
# end of sample
################################

Warnings:
Consolidation "MAX" instead "LAST": might give a different length of the blocks due to consolidation.
STEP=60 instead STEP=1: might give an consolidated maximum and not the absolute maximum of temperature.

You might play with the following script to see the differences in graphs:
The times and temperatures of the samples are: date: 2004-11-09
12:34:20  20 degrees
12:35:20  30 degrees
12:36:20  40 degrees
12:37:20  30 degrees
12:38:20  20 degrees
12:39:20   0 degrees
12:40:20   0 degrees
12:41:20  80 degrees
12:42:20   0 degrees
12:43:20  20 degrees

#######################################################
# sample script for temperature with some fixed values
#######################################################
CONSOLIDATION=LAST

STEP=1           # record one second steps
STEPSFORCDP=60   # use 60 steps to build a consolidated data point
let DURATION="24*60*60"  # one day with 24 hours which have 60 minutes which have 60 seconds
let TORECORD="\$DURATION/STEPSFORCDP/STEP"
MINTEMP=0
MAXTEMP=100
MINDATARATE=60
START=`date +%s`  # start database from now
START=1100000040
rrdtool create test.rrd --start \$START -s \$STEP \
DS:TEMPERATUR:GAUGE:\$MINDATARATE:\$MINTEMP:\$MAXTEMP \
RRA:\$CONSOLIDATION:0:\$STEPSFORCDP:\$TORECORD

# record your values every 60 seconds:
# endlessloop...
cat <<EOP | while read line
1100000060:20
1100000120:30
1100000180:40
1100000240:30
1100000300:20
1100000360:0
1100000420:0
1100000480:80
1100000540:0
1100000600:20
EOP
do
rrdtool update test.rrd \$line
done

# use the following command to show the graph of the last 24 hours:
SHOWSTART=`date -d "now -24hour" +%s`
SHOWEND=`date +%s`
SHOWSTART=1100000000
SHOWEND=1100000660

rrdtool graph test.gif -t "Temperature of the last 24 hours" --start \$SHOWSTART --end \$SHOWEND \
DEF:value=test.rrd:TEMPERATUR:\$CONSOLIDATION \
LINE1:value#00FF00:Temperatur

display test.gif
######################################################

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```