Actually, for data missing in the middle of a time period I would prefer it to use averages - this makes sense. The big problem I have is with missing data at the beginning of the first step - a 24hr step RRA is always going to over estimate if you start filling it sometime after midnight whereas the 5min step RRA won't.
e.g. if I create an RRD at 23:00 then I would always have 23 hours of over estimated data. /Chris On 28 December 2011 18:17, Chris Mason <[email protected]> wrote: >>>I am assuming the data that is missing at the beginning of the RRA >>>would be considered UNKNOWN and I would expect the TOTAL function to >>>ignore it? >> >> You may think that ... >> It depends on how it's calculated - the obvious calculation is average * >> time. >> The average function ignores unknown periods, so the average of >> unkn,1,2,3 would be 2 (6/3), not 1.5 (6/4). If you then multiply that >> by the period (4 samples in this case), it would give you 8 instead >> of 6. > > It comes down to whether you want unknowns to be 0 or the average. > As you say, it comes down to what the TOTAL function does: > > If I had 'U,1,2,3' then the average would be 2 but I would hope the > TOTAL function would use 3*2 to find the TOTAL. > But other people might want it to estimate the missing values using > the average - my interpretation is that if a value isn't there, then > you can't count it. > >> It's an interesting debate as to which is more accurate ! >> >> NB - I don't know the actual calculation that's used. I'll leave >> someone who knows the code to comment on that. _______________________________________________ rrd-users mailing list [email protected] https://lists.oetiker.ch/cgi-bin/listinfo/rrd-users
