[rrd-developers] How to create a new Data Type and Consolidation Function?

[Long V]

Hi Tobi,

Reply to your previous questions inline.


----- Original Message ----
> From: Tobias Oetiker <tobi at oetiker.ch>
> To: Long V <long_at_work at yahoo.ca>
> Cc: rrd-developers at lists.oetiker.ch
> Sent: Mon, April 11, 2011 3:32:43 AM
> Subject: Re: [rrd-developers] How to create a new Data Type and Consolidation 
>Function?
> 
> Hi Long,
> 
> that is exacly what makes me un-easy about your change ...
> RRAs witth different step size should still contain the same
> essential data ... just at a different resolution ... with your
> function this core premise of rrdtool gets pierced ...
> 

My function is keeping a SUM of the COUNTER difference. Let's illustrate with an 

example.

time           ___1 ___2 ___3 ___4 ___5 ___6 ___7 ___8
counter_value  _300 _450 _450 _900 1200 1800 2100 2550
diff_sum_res_1 _300 _150 ___0 _450 _300 _600 _300 _450
diff_sum_res_2    _450      _450      _900      _750
diff_sum_res_4         _900                1650

So at different resolutions, it's still the same "data" which is the "sum of the 

difference between each counter readings". 

> 
> Have you also added code to rrd_graph to properly resample based on
> the SUM consolidation function ?
>

I am not sure what you mean but I made the necessary modifications in rrd_graph 
to be able to graph a DS of type DIFFERENCE with multiple RRA level of type 
SUM. You can take a look in my provided patch.

> 
> what additions to the documentation have you made to explain the
> exotic properties of your new DST and CF ?
> 

I updated doc/rrdcreate.pod and doc/rrd-beginners.pod. You can take a look in my 

provided patch.

Thanks,
Long

>
> cheers
> tobi
>