[rrd-users] incoherent fetch and graph on year scale

[Tobias Oetiker]

Hi Sebastien,

Today Sebastien MICHEL wrote:

> it works if I create this db:
>  rrdtool create temp-LFBO.rrd --start $(date +"%s")   \
>              --step $TEMPS                       \
>              DS:temp:GAUGE:$((TEMPS * 2)):U:U    \
>              RRA:AVERAGE:0.2:1:$TEMPS            \
>              RRA:AVERAGE:0.2:6:168               \
>              RRA:AVERAGE:0.5:12:372              \
>              RRA:AVERAGE:0.8:144:3650
> and not
>              RRA:AVERAGE:0.8:144:36500
>
> I think it's a bug with db can store data older than 1970 or
> 1988.
>
> what do you think ?

rrdtool relies on the operating systems time funcitons ... many 32
bit oses have issues in dealing with time before 1970 or after 2036
rrdtool itself does not have these issues by design, but it may be
that you trigger corner cases by going over these limits.

cheers
tobi

> Le mardi 13 octobre 2009 à 15:03, Sebastien MICHEL a écrit:
> > hey,
> >
> >   I would like to know if my problem is an rrdtool bug or
> >   a usage problem.
> >
> > I am on unstable debian and use :
> > RRDtool 1.3.8  Copyright 1997-2009 by Tobias Oetiker
> > <tobi at oetiker.ch> Compiled Jun  2 2009 18:23:37
> >
> > works :
> > rrdtool fetch data/temp-LFBO.rrd --start "-31d" --end now
> > AVERAGE
> >
> > doesn't works:
> > rrdtool fetch data/temp-LFBO.rrd --start "-32d" --end now
> > AVERAGE rrdtool fetch data/temp-LFBO.rrd --start "-1y"
> > --end now AVERAGE
> >
> > the "rrdtool fetch data/temp-LFBO.rrd --start "-32d" --end
> > now AVERAGE" result is a part of the first sample of
> > "rrdtool dump data/temp-LFBO.rrd" strange isn't it ?
> >
> > You can get the database here:
> > http://meteo.falguerolles.org/data/temp-LFBO.rrd
> >
> > To create my db:
> > rrdtool create temp-LFBO.rrd --start $(date +"%s")   \
> >             --step $TEMPS                       \
> >             DS:temp:GAUGE:$((TEMPS * 2)):U:U    \
> >             RRA:AVERAGE:0.2:1:$TEMPS            \
> >             RRA:AVERAGE:0.2:6:168               \
> >             RRA:AVERAGE:0.5:12:372              \
> >             RRA:AVERAGE:0.8:144:36500
> > # "RRA:AVERAGE:0.2:6:168", # moy sur une heure pour tout
> > une semaine => 6data * 10min = 1h : 24h * 7j = 168 #
> > "RRA:AVERAGE:0.5:12:372", # moy sur 2heures pour tout un
> > mois => 12data * 10min = 2h : 372 = 12 * 31 valeur = 12
> > valeurs par jour # "RRA:AVERAGE:0.8:144:365" # moy sur un
> > jour pour un ans => 24h * 6data =144data pour une journee
> > : 365jours (valeurs) par ans * 100 years.
> >
> > thanks, regards,
>
>

-- 
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