[rrd-users] help required to graph photovoltaic electricity savings

Dossy Shiobara dossy at panoptic.com
Wed Nov 28 18:39:50 CET 2012

On 11/28/12 11:04 AM, Thomas Parvais wrote:
> That seems easy to implement for the RRD create and RRD update
> However, I wonder if Average will be well computed as the average
> should be done for the the relative period 0700-1900 or 1900-0700 and
> not over 24h.
> We can have also real measurement = 0.

Ah, you're absolutely right -- you should be recording the data points
as "U" unknown, not zero -- that's right.

The trick is going to be getting rrdgraph to not plot anything where
data points are unknown, instead of either treating unknown as zero OR
most recent value.  You may need to define CDEF's to handle the unknown
values properly and graph the CDEF's instead of the raw DEF/DS data.

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