[rrd-users] Fetch the time of the first entry

Alex van den Bogaerdt alex at vandenbogaerdt.nl
Tue Jul 1 16:08:36 CEST 2014

> Simon;
> Something is seriously wrong and I don't know what it is.
> My Perl script parses the data file just fine.
> It plots just fine.
> The legends are correct
> The dates are correct.
> BUT when I use rrdtool first <rrd database> in an attempt to get the time
> of the first entry, I get a Unix time stamp which is one entire month
> EARLIER than the first entry in the file.

As already explained, "rrdtool first" gives you the first available slot.

Maybe you want to look at the data provided by the VDEF function "FIRST".

    Return the last/first non-nan or infinite value for the selected data
stream, including its timestamp.

    Example: VDEF:first=mydata,FIRST"

If you "rrdtool graph" without actually using any graphing elements, and
the PRINT (not GPRINT) this value's time component, you can use it in a


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