[rrd-users] Biased graph - shifted average periods

Simon Hobson linux at thehobsons.co.uk
Thu Jun 25 08:49:13 CEST 2009

Igor I.  Shulz wrote:

>I've created rrd-file to accumulate data on a per-hour-basis (--step 
>3600). Thre are two AVERAGE sets:
>--start set on the edge of a day - 1242248400
>But 4-hour averages are not set on even 4-hour ranges (00:00, 04:00, 
>08:00 etc), but are set on ranges 03:00, 07:00, 11:00.
>Is it possible to set average periods on the more reasonable points?
>00:00, 04:00 ... for 4-hour average
>00:00, 00:00 ... for daily average

What is the local timezone on the server ? I'm guessing that since 
your email says +4, your server might be set to +3 and this would 
account for your problem.

RRD uses UTC, and all steps are aligned on Unix epoch (ie "start of 
time" at midnight 1st Jan 1970). Hourly/daily etc steps will always 
be aligned on midnight UTC.

It's been discussed regularly in the past, but I can't recall what 
teh answer was.

Simon Hobson

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