[rrd-users] newbie rrd question - probably a very old issue

[Dan Gahlinger]

Sounds like this is in dire need of a FAQ! :)

so why does rrd dump and rrd fetch show different results?
I'll check the "--resolution" option before continuing that question.

and I could swear I "fixed" this problem with a simple modification to the 
RRA definition.
I'm almost positive it had something to do with "ABS", but that was 5 years 
ago.


>From: Tobias Oetiker <tobi at oetiker.ch>
>To: Dan Gahlinger <dgahling at hotmail.com>
>CC: jfesler at gigo.com, rrd-users at lists.oetiker.ch
>Subject: Re: [rrd-users] newbie rrd question - probably a very old issue
>Date: Sat, 1 Sep 2007 20:49:26 +0200 (CEST)
>
>Dan,
>
>note that rrdfetch is NOT consolidating anything, it shows you what
>is stored in the rrd ... if you want to see what is actually
>stored, use rrdtool dump ...
>
>you may also want to read through the mailinglist archives, since
>we get someone like you every few months how needs many days of
>patient explaining until he understand why rrdtool is designed the
>way it is designed and why it works the way it works, and why this
>is the right thing todo ... (it has been like this for the last 8
>years actually and tousands have used and understood the logic) ...
>you will get there ...
>
>cheers
>tobi
>
>
> >
> > that's not exactly what I want.
> >
> > to be honest, I'd be happy if rrd did one simple thing (or two depending 
>on
> > your point of view).
> >
> > I'd recommend the "min" and "max" of the average function be done a bit
> > differently.
> > for an average graph, the "maximum" (shown at the bottom) should always 
>be
> > kept,
> > and the "minimum" should always be kept
> >
> > also the points for those on the graph should always be kept, even if it 
>means
> > the verticals in the graph are stretched a bit.
> >
> > the graph doesnt have to show ever portion of the scale either. by this 
>I mean
> > if there are no values between 10 and 40, you dont need to show the 
>portions
> > from 11-39 essentially
> > as long as the maximum, minimum and average are represented properly
> >
> > it should be simple enough to keep track of the minimum and maximum over 
>time.
> > my logic:
> > if you have a spike of 100 one day and that is you maximum, then a week 
>or a
> > month or a year later, if that is still your maximum, then it is always 
>your
> > maximum, and the spike should be shown
> > today it should be the max, tomorrow it should be the max, and until a 
>higher
> > value occurs, it should always be the max, same with minimum, if we got 
>a
> > zero, that will always be the minimum. and the overall average should be 
>the
> > average between those two values.
> >
> > otherwise the data is incorrect and quickly becomes meaningless.
> > yesterday it spiked to 90, but today it shows the max is only 30, so did 
>it
> > spike? not according to the graph it didnt.
> >
> > and I still dont understand why the command line (rrdfetch) is 
>consolidating,
> > it has no graphing limitations
> >
> > I don't know a better way to do it.
> > Dan.
> > > From: Jason Fesler <jfesler at gigo.com>
> > > To: Dan Gahlinger <dgahling at hotmail.com>
> > > CC: tobi at oetiker.ch, rrd-users at lists.oetiker.ch
> > > Subject: Re: [rrd-users] newbie rrd question - probably a very old 
>issue
> > > Date: Sat, 1 Sep 2007 10:09:32 -0700 (PDT)
> > >
> > > Based on a side conversation with Dan, this is what I'm understanding:
> > >
> > > RRD will graph exactly one consolidated point in time, if there are 
>more
> > > points than pixels on the X axis.  Dan wants *all* value points 
>represented,
> > > not consolidated.  RRD has no option to do that.
> > >
> > > I'm thinking that *maybe* it can be faked, with some stacked graphs or
> > > something, *if* MIN and MAX were also included in the rrd file; do a 
>fill
> > > between min and max.
> > >
> > > But it isn't going to happen with a single graph statement, and I'm 
>having
> > > problems figuring out how to sanely show min/average/max if desired. 
>:-)
> > >
> >
> > _________________________________________________________________
> > Show Your Messenger Buddies How You Really Feel
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> >
> >
>
>--
>Tobi Oetiker, OETIKER+PARTNER AG, Aarweg 15 CH-4600 Olten
>http://it.oetiker.ch tobi at oetiker.ch ++41 62 213 9902

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