[rrd-users] Numbers

[Simon Hobson]

Paul Halliday wrote:

>I will begin by saying my math is terrible - this might be right.
>
>Here is two runs:
>
>what I put in:
>
>4297607 || 3460967
>
>What I get:
>
>4.0777821933e+06 || 3.3850085800e+06
>
>Is this right?
>
>
>my rrd declarations look like:
>
>rrdtool create $rrd_dir/in_out_in_test.rrd --start `date -v0H -v0M
>-v0S "+%s"` DS:in_out_in:GAUGE:600:U:U RRA:LAST:0.5:1:105120
>rrdtool create $rrd_dir/in_out_out_test.rrd --start `date -v0H -v0M
>-v0S "+%s"` DS:in_out_out:GAUGE:600:U:U RRA:LAST:0.5:1:105120
>
>I have tried absolute .. average as well and I get the same numbers.

There isn't enough information there to be sure, but I'll guess that 
the timestamp of your updates is not on a step boundary (ie an 
integer multiple of step since unix epoch). If your updates are not 
exactly on a step boundary, then rrd will normalise the values - it 
adjusts the figures to fit the fixed 'bins' it has to put the data 
into.

Alex has some excellent descriptions of this on his website :
http://www.vandenbogaerdt.nl/rrdtool/

-- 
Simon Hobson

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