# [rrd-users] Rrdtool for counting irregular events

Simon Hobson linux at thehobsons.co.uk
Sun May 20 17:44:32 CEST 2012

```Rafal Gwizdala wrote:
>Whoa, not so fast. TOTAL is available for VDEF only so I can
>calculate the total for the whole graph only. Still don't see a way
>to do the same for each aggregation step shown on the graph.

If your step period for the graph is (say) 1800s, then do :
x=a,1800,*
where a is your stored rate, and then plot x.

>If there was some variable representing graph's time resolution I
>could use it for calculating sums the way you described
>CDEF:total=myvalue,GRAPHRESOLUTIONSECS,*

There is, but you need to work it out before you call the graph. When
I do graphs, I work out what resolution I'm going to plot and work
from there. So I tend to do something like :
case period in
day
step=300; time=86400 ;;
week
step=1800; time=604800 ;;
...

Then I work out start and end times :
e=`date +%s`
end=\$(( \${e} / \${step} * \${step} ))
start=\$(( \${end} - \${time} ))

So in Bash, \$end is now the exact time at the end of the last
complete period, and \$start is that time less the length of the graph.

I can now use "--start \${start} --end \${end}" in the graph
definition, and of course, you can also use \$step in calculations :
x=a,\${step},*
for example.

--
Simon Hobson

Visit http://www.magpiesnestpublishing.co.uk/ for books by acclaimed
author Gladys Hobson. Novels - poetry - short stories - ideal as
Christmas stocking fillers. Some available as e-books.

```