[rrd-users] Newbie question: Always missing the last datapoint in rrdtool graphs

Ole Holm Nielsen Ole.H.Nielsen at fysik.dtu.dk
Thu Feb 26 13:26:19 CET 2009

Hi Len,

I'm pleased to hear that it's possible to map daily 24-hour data into a
single timestep in an RRD database.  Being an rrdtool newbie I'm unsure
how to get the timestampts *exactly* right for 24-hour data, so I wonder
if you or someone else could show me example commands like:
    rrdtool create $RRDDB --start $STARTTIME --step $STEPTIME ...
    rrdtool update $RRDDB timestamp...
    rrdtool graph $RRDDB --end $last --start $starttime ...

For the "update", which timestamp value must be chosen: 00:00:00 or
24:00:00 = 00:00:00 next day ?

For the "graph", what are magic start and end values that will produce
a nice daily graph ?

Thanks a lot,

Leonard Mills wrote:
>> One point makes me really worried, though, namely your explanation
>> of the timezone problem.  I do live in the UTC+1 timezone (and UTC+2
>> during the summer), so you're telling me that I'll *never* be able to
>> map my daily 24-hour data into a single timestep in an RRD database ??!!
> Sure you can.  Just run the data in UTC.  It's easy, and almost
> everyone does it.  00:00:00-23:59:59.999... for each data point.
> Len

Ole Holm Nielsen
Department of Physics, Technical University of Denmark

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