Thanks all for the replies. The good thing was is that they all said the same thing. I'm ok with that but it's not really the current data that I have a problem with But the graphs for last day, week, month and year show really off values for "now".
Does it make sense to show this value on those screens at all? Thanks again, jon -----Original Message----- From: Steve Shipway [mailto:[email protected]] Sent: Tuesday, May 27, 2014 5:43 PM To: Silver, Jonathan; [email protected] Subject: RE: [rrd-users] How is the "now" value is calculated Avast, ye swabs; John Silver told I: > Each graph has a "now" value display as part of that graph and I'm wondering > from where and how that value is calculated. Our metrics are all defined as > gauges (because they com through various tooling like sflow or jmxtrans or > gmetric. some support type, other do not). > > The metric I'm collecting is an integer counter. But I'm sometimes seeing the > max (and last) value as NN.nn where nn is not 00. Why would this (or the > max value) never always be a whole number? The short answer is Data Normalisation. This is explained in Alex van den Bogeardt's tutorial here: http://www.vandenbogaerdt.nl/rrdtool/process.php The long answer is that RRDTool will adjust incoming values using a linear approximation in time in order to make them fit into strict time samples. So, if your RRD is set up with a 1-minute step, it expects all samples to arrive precisely on the 1minute boundary when the number of seconds is 0. If the data arrive after this (such as at 12:00:15 instead of at 12:00:00) the values are normalised to what they would have been expected to be at this earlier time. This results in the fractional values you are experiencing. It is important to realise that RRDTool treats all values as Rates, and this normalisation does not affect the overall rate or total. Steve Steve Shipway [email protected] _______________________________________________ rrd-users mailing list [email protected] https://lists.oetiker.ch/cgi-bin/listinfo/rrd-users
