Re: Graphing inconsistencies graphing different time slices

Simon Hobson <[email protected]>
Newsgroups gmane.comp.db.rrdtool.user
Message-ID <[email protected]>
Munroe Sollog <[email protected]> wrote:

> I have an inconsistency when I graph the same event over 10days versus 48hrs.  I would expect
> because I am using MAX that the peak on the 48hr graph and the 10day graph for the *same* event
> would still read the same number.  However, the peak for Sunday noon on the 48hr graph is at 600,
> and the peak for that same period on the 10day graph is *higher* at 1.1k.  I believe I have
> included all the necessary files below.  I didn't want to paste the raw info here as it would be
> very large.  Any insight would be appreciated.

You are adding up different max values. Consider this set of data :
a1 = 1 5 3 7 4
b1 = 2 6 9 1 4

If you do a graph of max (max a + max b) without any consolidation then you get the values :
m1 = 2 11 12 8 8

If you consolidate 5 values into one, you then get :
a2 ave = 4
a2 max = 7
b2 ave = 4.4
b2 max = 9

m2 (= max (max a2 + max b2)) = 16

So when you draw a graph over a longer time period, depending on the consolidation, you may see your maximum value go up (with these made up figures, by 1/3) when you add max values together.
lmpx.com only provides a reader for public news (NNTP) servers. It is not affiliated with the servers or forums shown here and is not responsible for the content of articles, which is written by their respective authors.