# [rrd-users] Re: How to draw a sum over a time range?

Alex van den Bogaerdt alex at ergens.op.het.net
Mon Apr 10 14:09:29 MEST 2006

```On Mon, Apr 10, 2006 at 10:57:13AM +0200, Joerg Maschtaler wrote:

> I want to draw a graph with the sum of collected data for each month
> over a year but i don't know how.

This sounds like a job for another type of program.

> The graph should be updated once a day.
>
> The rrd is updated once a day and provides data since 04.04.2006.
> It was created with
> - step 86400
> - DS:in:DERIVE:86400:0:U
> - RRA:AVERAGE:0.5:1:500

So, you have one interval per 24 hours UTC time.

> To create the graph i do the following:
> - start 00 20060101
> - end 00 20070101

which will need to be adjusted by rrdtool because you don't live
in Iceland (are there other countries living on GMT time and not
having daylight saving / summer time ?).

> - xgrid MONTH:1:YEAR:1:MONTH:1:2592000:%m
> - DEF:in=file.rrd:in:AVERAGE
> - CDEF:intotal=in,UN,0,in,86400,*,IF
> - AREA:intotal#32CD32:Incoming
>
> Now i want to accumulate all values of a month and then draw the total
> for each month.

RRDtool uses fixed-width intervals by design.  A month has no specific
length:

Januari:  744 hours
Februari: 672 hours, or 696 in about one out of four years
March:    743 hours (assuming summer time kicks in)
April:    720 hours
May:      744 hours
...
October:  745 hours (assuming end of summer time occurs here)
November: 720 hours
December: 744 hours

> Is it possible (and if yes, how)?

Sure this is possible, but not with rrdtool.

> Aside from that is it possible to write the total of each month in the
> corresponding area, maybe as vertical text?

You need a drawing program, not rrdtool.

--
Alex van den Bogaerdt
http://www.vandenbogaerdt.nl/rrdtool/

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