[rrd-users] rrdtool - features ... 2nd y-axis

Karl Fischer rrd-users at ficos.de
Sun Jun 1 12:44:05 CEST 2008

Tobias Oetiker wrote:
> If you now store everything as integer, this resampling process
> will loose precision which is realy not something you would want
> todo to your data.


> So if you insist on storeing your data as integers, you would have
> 3 options:
> a) devise a magical way that enables you to collect all data at
>    exactly time % step == 0
> b) lie about the data collection time, and fill in the data that
>    you collected at time % step == x at time % step == 0
> c) use a  generic (SQL) database where you can store the data you
>    collected as well as the time you did collect the data.

It looks like for this special purpose I'll have to define my own
data model ...

> The interesting thing is to select a samping interval that is
> correct for the rate of change in the data you are observing.

That's exactly the point:
I don't need to sample data at a 1min interval during hours where
nothing happens, however, during busy times a 1sec interval might
be apropriate ...
So here we're talking about another requirement apart from storing
exact values - I'd prefer to do the interpolation of missing values
at the fetch-time, not at the store-time - saving space in the DB.

I like the idea of a round-robin-database very much, however, the
implementation of rrdtool doesn't always do what I would like it to.

I even thought about storing the data in some other form (generic db)
and put it into rrdtool just for the graphing ...

So - I opened this discussion - let me close it here, it doesn't lead
anywhere. I don't want to offend you since I really do appreciate what
you've done with this great tool - it just doesn't meet my requirement.

What I need (for this purpose) is a different database model with the
same graphing features rrdtool has - that's why I thought about some
changes to the underlying db and keeping a big portion of the rest.

Many thanks for all.

- Karl

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