Rafal Gwizdala wrote: >Or maybe the step can be calculated based on graph date range? If >so, what's the algorithm rrdtool uses?
It should attempt to use the most detailed data that will fill the graph most fully. If you have consolidations where every consolidation is a multiple of the shorter ones (eg, 30mins is a multiple of 5 mins, 2 hours is a multiple of both 30 and 5 minutes, and so on) then this will normally mean using the most detailed data available. Example, you consolidate over 5 minute intervals for one day, and 1/2 hour over one week. If you ask for a graph which starts not more than 24 hours ago, then you'll see 5 minute data. Go back a few minutes more and you'll get 1/2 hour data as the 5 minute data won't fill the graph. This is because there is never a situation where a lower resolution consolidation covers a period that isn't also covered by a higher resolution one - at least as far back as the higher resolution data goes. Where it breaks down is if the consolidated periods are multiples of each other. Suppose you consolidate over 2 minutes and 5 minutes. Graph from midnight (00:00) to 00:14 and you'll get 7off 2 minutes samples. Graph from midnight to 00:15 and you may get 3off 5 minute samples as that will fill more of the graph. From memory, you can force the resolution to be used - which would result in the 15 minute graph showing the more detailed data with a gap at the end (if you forced the 120s resolution). I also believe some changes have been made since I last took any notice of this and I don't know what changed. -- Simon Hobson Visit http://www.magpiesnestpublishing.co.uk/ for books by acclaimed author Gladys Hobson. Novels - poetry - short stories - ideal as Christmas stocking fillers. Some available as e-books. _______________________________________________ rrd-users mailing list rrd-users@lists.oetiker.ch https://lists.oetiker.ch/cgi-bin/listinfo/rrd-users
