perfect explaination! thank you very much! last thing I dont get is the fact that all the data now is moved by 5 minutes to the right or so..
I attached the new, fixed script. On 03/26/2014 10:47 AM, Alex van den Bogaerdt wrote: > I think you're missing the fact that RRDtool uses timestamps based on UTC. > When you specify "--step 86400" you are telling RRDtool to create a database > with start and end times which are a whole multiple of 86400 seconds. > > Your first timestamp is 1395140400 which is n*86400+39600. > Your second timestamp is 1395226800 which also is n*86400+39600. > I did not check the rest but I can safely assume the rest will not be > different. > > Normalization massages the input so that it fits in (n-1)*86400 to n*86400 > time intervals. > > The rate computed at 1395226800 is valid partially in the interval upto > 1395187200 and partially thereafter. To be precise, (86400-39600)/86400 > stays in the timeslot computed for 1395187200 and 39600/86400 goes to the > next timeslot. > > Your next update is at time 1395313200. Now there is enough data to compute > the timeslot between 1395187200 and 1395273600. The rate logged at time > 139573600 should be 39600/86400 * 3 + 46800/86400 * 2 = 2.458333.... > > HTH > Alex > > > ----- Original Message ----- > From: "Peter Thurner" <[email protected]> > To: <[email protected]> > Sent: Wednesday, March 26, 2014 10:24 AM > Subject: [rrd-users] cant get to understand described normalization > behaviour > > > Hi guys, > > I'm kind of dying on this one. I attached 3 bash scripts that show where > I don't understand things anymore. I guess its quite simple. > > I feed the same values using the same CF and RRD specs everywhere, but > on the script rrdtest-days.sh, I get a graph that is a lot different to > the other two scripts. > Other than the --step size I did not change much (as a diff would show). > > Why (and how?) is it normalizing when all I increase is the timespan > between updates? I'm sure I missed something.. > > Thank you very much in advance! :) > > Peter > > > > -------------------------------------------------------------------------------- > > >> _______________________________________________ >> rrd-users mailing list >> [email protected] >> https://lists.oetiker.ch/cgi-bin/listinfo/rrd-users >> > > _______________________________________________ > rrd-users mailing list > [email protected] > https://lists.oetiker.ch/cgi-bin/listinfo/rrd-users >
rrdtest-days-utc.sh
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