[rrd-developers] DS idea

Tobias Oetiker tobi at oetiker.ch
Mon Oct 11 09:04:15 CEST 2010


Today Alex van den Bogaerdt wrote:

> ----- Original Message -----
> From: "Tobias Oetiker" <tobi at oetiker.ch>
> To: "Alex van den Bogaerdt" <alex at vandenbogaerdt.nl>
> Cc: <rrd-developers at lists.oetiker.ch>
> Sent: Monday, October 11, 2010 8:05 AM
> Subject: Re: [rrd-developers] DS idea
> > Hi Alex,
> >
> > Today Alex van den Bogaerdt wrote:
> > [...]
> >
> >> That is because in that example, I want MAX, not LAST.
> >
> > for MAX and MIN it would work I agree ...
> The OP:
> "However, part of the collected samples are maximum wait times of queueing
> systems. These numbers are not guesswork but calculated exactly while
> servicing. I am very much interested in seeing the maxima of these maximum
> wait times later when I query a MAX-RRA. Currently, RRD interpolates to the
> grid first and than computes the maximum."
> So MAX is what is needed.
> And why do you only agree for MIN and MAX, thus implicitly not for LAST ?

it would work for LAST but not for AVERAGE as higher interval RRAs
could not work of a the base step of 300 since it was set to 1.

> In case you worry about further consolidation: don't. I think there will
> always be that one corner case where someone wants the last of the input,
> and then use max for further consolidation. Or vice versa. Or similar.
> Sometimes rrdtool is just not the right tool for a job.
> Creating new DSTs is not the way to go imho. Especially not if the tool can
> do what is asked from it.

Do you agree that the GAUGELAST would also solve the problem ?

My motivation for this is that it would provide a good solution to
the 'I want my input value stored' questions coming up at regular

Tobi Oetiker, OETIKER+PARTNER AG, Aarweg 15 CH-4600 Olten, Switzerland
http://it.oetiker.ch tobi at oetiker.ch ++41 62 775 9902 / sb: -9900

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