[rrd-users] clear values from RRA

[A Darren Dunham]

On Wed, Jan 14, 2009 at 12:13:25AM +0100, Levente Kovacs wrote:
> Hi,
> 
> http://logonex.eu/tc/
> 
> I have another question. If you see my temperature sensor test site, you may
> realize the very first values of the blue and green lines to be -60. It is
> because my hardware has 3 ports, but only one (red) had an actual sensor
> connected to it. The unconnected ports read out the minimum measurable value,
> that is -60deg.
> 
> Anyways... I'd like to clear those values from my RRAs. How can I do it?
> Shlould I write a perl script which modifys the XML dump? If I do so, and when
> I restore the data... will the newly aquired data lost which were recorded
> during the process of the XML?

You could continue collecting data yourself (perhaps just to a text
file).  Insert that data after the conversion is complete and you won't
have lost any data.

> Or is there any way inside the RRD system to do say "do this and that with
> values smaler and/or larger then X".

You can set up a CDEF from your data at graph time that ignores values
smaller than X, then graphs that data rather than the recorded RRA data.

-- 
Darren