Ben Griffith wrote: >Doesn't it just add up all the entries to get a total for the hour, >then from that a rate per second? Or does it actually compute the >rate throughout the hour, on the fly?
No, it ALWAYS computes an average/max/min depending on what you set in the rrd. Also, you NEED to use average or your figures are guaranteed to be wrong. For example, suppose we just look at 4 samples : 1 1 0 0 Clearly your boiler was running for half the time (give or take a bit due to the sampling), and average would give you 0.5. Max would give you 1 for any period where the boiler ran at all which is not what you want. > > I tried supplying start and end times in the DEF, but the boundaries are >> still always placed at 19:00. How can I change that? > >Find a way to work with 24 hourly values instead of 1 daily value. > > >This is the method I chose. Here's what I came up with: > >filename=/usr/local/misterhouse/trunk/data/rrd/Burner_Counter.rrd >timenow=`date | sed 's/:/\\\:/g'` >rrdtool graph /home/griffith/public_html/boiler_day.png \ > --end 00\:00 --start end-7d --x-grid >DAY:7:DAY:7:DAY:1:86400:%A \ > --height 200 --width 500 --imgformat PNG \ > --title "Boiler run-time per day" --vertical-label "minutes" \ > DEF:day1=$filename:minutes:MAX:start="midnight >yesterday - 6d":end=start+23h \ Two things wrong here (I think) : First, you don't want max, you want average (see above) Second, I think you need "start+24h" not "start+23h" I think something similar came up a while ago on this list, and the suggestion was something like if time of day <=19:00 then do one calculation else do a slightly different calculation I can't remember any more detail about it. _______________________________________________ rrd-users mailing list rrd-users@lists.oetiker.ch https://lists.oetiker.ch/cgi-bin/listinfo/rrd-users