[rrd-users] couple of questions

[A Darren Dunham]

On Wed, Sep 08, 2010 at 01:26:02PM -0700, Ricardo Kleemann wrote:
> Thanks Simon.
> 
> I'm not yet very familiar with rrdtool, but could I read out data
> values for an arbitrary period between time1 and time2 and add up the
> values to come up with accumulated?
> 
> I was thinking of a page where I could choose the dates and then have
> a graph drawn for those dates, including the accumulated values as
> well.

Simplest is to pass that to rrdgraph as new --start and --end times and
then use a TOTAL VDEF to sum them.

If you truly want to sum something that is only a subset of the graph,
I'd probably try to construct a CDEF from the original data and have it
nulled out outside the region of interest.  Then run TOTAL on it as above.

> >I would like to also display an accumulated counter (say total?
> >bandwidth for the month), how would I do that on the graph and on?
> >the rrd table?

If you generate a total with a VDEF, you can print it as part of the
legend with GPRINT or to stdout with PRINT.  I don't really know what
you mean by "on the graph".

-- 
Darren