Hi Tobi > 3. Finally, is there any patch to add SUM function for totalizing a > metric over a period. This is a very important requirement as we need to > count the total number of certain events for minute, hour and day. I'm > aware of the approach of using the average and multiplying by the > reporting period, but this will lead to a approximated value. > everything in rrdtool is a 'rate' so even if there was such a > function the math would still be the same ... can yo elaborate in > what way you expect the result of the calculation to be an > aproximation? >
According to what I read in the previous discussions on this list (https://lists.oetiker.ch/pipermail/rrd-developers/2005-April/001405.html) The presence of unknown values may produce wrong totals when calculating the total from the average. For example: > 0:UNKN 300:10 600:10 900:10 > > consolidated and then mulitplied by the period will produce the same value > as if all entries were 10, and not with one UNKN (given the cf is 0.5). A > SUM function would nicely return 30. > Regards Pablo On 10/29/2012 10:16 PM, Tobias Oetiker wrote: > Today Pablo Chacin wrote: > >> Greetings all >> >> I'm new to rrdtools. I'm actually still evaluating it as as tool for >> storing monitoring metrics. >> After reading the documentation and several discussions in this list and >> also in other forums >> I'm still confused about a couple of things. >> 1. How are subsecond timestamt reported? In several places it is >> mentioned the existence of these timestamps, but can't find any example >> of how to specify it in the update command, except when using "N" as >> timestamp. > rrdtool update 1351545246.3897:394.33 > >> 2. Supposing subsecond timestamps are supported by rrdtools, are they >> also supported by rrdcached? > I think the version on github does support it ... the released > version not. >> 3. Finally, is there any patch to add SUM function for totalizing a >> metric over a period. This is a very important requirement as we need to >> count the total number of certain events for minute, hour and day. I'm >> aware of the approach of using the average and multiplying by the >> reporting period, but this will lead to a approximated value. > everything in rrdtool is a 'rate' so even if there was such a > function the math would still be the same ... can yo elaborate in > what way you expect the result of the calculation to be an > aproximation? > >> Even when >> I understand the concerns about it not working properly in all >> situations, I think is a very common requirement. Simply can't believe >> nobody has done this ever, unless I'm completely wrong about the need of >> such function. > cheers > tobi > >> many thanks in advance >> >> >> -- Pablo Chacin R&D Engineer SenseFields SL Tlf (+34) 93 418 05 85 Baixada de Gomis 1, 08023 Barcelona (Spain) http://www.sensefields.com/ _______________________________________________ rrd-users mailing list [email protected] https://lists.oetiker.ch/cgi-bin/listinfo/rrd-users
