[rrd-users] Difficulty getting rrdtool to store "daily" information

Simon Hobson linux at thehobsons.co.uk
Fri Feb 16 20:08:12 CET 2007

Bill Moran wrote:

>rrdtool update /var/www/bacula/jobs.rrd 1171083600:68440880988
>rrdtool update /var/www/bacula/jobs.rrd 1171170000:384966685
>rrdtool update /var/www/bacula/jobs.rrd 1171256400:7604606807
>rrdtool update /var/www/bacula/jobs.rrd 1171342800:5511113163
>rrdtool update /var/www/bacula/jobs.rrd 1171429200:7160839755
>Now, an XML dump of the rrd shows me _very_ different data than what I would
>expect: (trimmed for clarity, let me know if I need to provide the whole


><!-- 2007-02-09 19:00:00 EST / 1171065600 --> <row><v> NaN </v></row>
><!-- 2007-02-10 19:00:00 EST / 1171152000 --> <row><v> 
>4.4556329282e+03 </v></row>
><!-- 2007-02-11 19:00:00 EST / 1171238400 --> <row><v> 
>7.0607813830e+04 </v></row>
><!-- 2007-02-12 19:00:00 EST / 1171324800 --> <row><v> 
>6.8834000835e+04 </v></row>
><!-- 2007-02-13 19:00:00 EST / 1171411200 --> <row><v> 7.8902161053e+04

>Now those e+04, e+03 values are way lower than what I put in.  I'm 
>guessing that somewhere rrdtool is still averaging that data over 
>some period or something, but I'm at a loss as to what I can do to 
>get it in there the way I want it.
>I thought the MAX declarations would take care of it, but I must still be
>missing something.

If you try, you will find that (for example) 384966685 / 86400 is 
about 4.45e+03

RRD tool stores RATES, therefore when you stuff a value in each day, 
it divides by 86400 to get a RATE for the day (it also does stuff to 
adjust for updates not occurring on sample boundaries but that's 
another matter). So to get the total amount for the day, just 
multiply by 86400 (number of seconds in a day).

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