[rrd-users] graph lines differ from actual values

[Steve Shipway]

Are your date timestamps precisely on the RRDTool step boundaries?  If not
then there will be some consolidation and calculation going on in there, I
think.

I don't know enough about the data you're graphing -- its regularity, it's
interval, and so on, or about the graph interval you are using to be able to
deduce what consolidation or adjustments may be taking place.

You might want to use the /rrdminstepsize option to let RRDTool know the
minimum step of your table's data; also the /rrdfillmissing option to extend
steps if there are insufficient in the table for what rrdtool needs.

Steve

Steve Shipway
s.shipway at auckland.ac.nz

-----Original Message-----
From: rrd-users-bounces+s.shipway=auckland.ac.nz at lists.oetiker.ch
[mailto:rrd-users-bounces+s.shipway=auckland.ac.nz at lists.oetiker.ch] On
Behalf Of John Stile
Sent: Tuesday, 8 April 2014 7:56 a.m.
To: rrd-users
Subject: [rrd-users] graph lines differ from actual values

I am using rrdtool, libdbi, and mysql to chart thermal data.

I noticed the lines are sometimes a little higher than the actual data being
plotted, and I would like them to match.

Is there something I can change to make the graphed data match the actual
data?
DEF:cpuPhym=sql//mysql/host=127.0.0.1/dbname=thermal/username=foo/password=b
la//temperature/*date/cpuPhy/:min:AVERAGE
LINE:cpu0#f601b488:cpu0\\:GPRINT:cpu0:AVERAGE:\%-6.2lf${degree}C COMMENT:\\n



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