[rrd-users] Re: RRA:MAX not acting like I thought when "multiple updates in a single step"

[Jean-Francois Patenaude]

Alex, thanks for your 10000 feet ASL answer but I needed something
more technical.

I read the source code and understood why it doesn't work.  Every update,
during a single step, is always considered as a fraction of the step
and it pulls the overall value according to the fraction (the interval)
it is valid for.  This kind of behavior is well suited for average
consolidation but lacks precision when MIN/MAX values are looked at.

I also noticed that a strong rewriting would be needed to achieve a clean
solution for what I thought could be simplier.   A small/crude patch is
still possible (see attachment).   I would appreciate someone to review it ..

Of course, as you mentionned earlier, the best way to achieve the MIN/MAX
I was looking for is to have a finer grain step (i.e. 1 second)    But
in this case, I would get much larger RRD files which I really don't want.

Jf.



On Mon, 11 Aug 2003, Alex van den Bogaerdt wrote:

> On Mon, Aug 11, 2003 at 09:45:45AM -0400, Jean-Francois Patenaude wrote:
> > 
> > > You asked for 60 seconds per interval.  None of the 60-second intervals
> > > had a maximum rate of 50.
> > 
> > I thought the following line meant that, at some point, we had a value of
> > "50" somewhere in the 60 seconds interval.
> 
> That you update multiple times in the interval isn't relevant.
> 
> In the RRA:
> Nothing is known, except the start and the end of the interval.
> 
> If you know this, it isn't hard to grasp why your rate of 50 isn't
> visible.
> 
> Alex
> 
> --
> Unsubscribe mailto:rrd-users-request at list.ee.ethz.ch?subject=unsubscribe
> Help        mailto:rrd-users-request at list.ee.ethz.ch?subject=help
> Archive     http://www.ee.ethz.ch/~slist/rrd-users
> WebAdmin    http://www.ee.ethz.ch/~slist/lsg2.cgi
> 
> 


-- Attached file removed by Ecartis and put at URL below --
-- Type: text/plain
-- Size: 2k (2058 bytes)
-- URL : http://www.ee.ethz.ch/~slist/p/min_max_precision.patch


--
Unsubscribe mailto:rrd-users-request at list.ee.ethz.ch?subject=unsubscribe
Help        mailto:rrd-users-request at list.ee.ethz.ch?subject=help
Archive     http://www.ee.ethz.ch/~slist/rrd-users
WebAdmin    http://www.ee.ethz.ch/~slist/lsg2.cgi