> > From: Alex van den Bogaerdt > > I think this is not the case. An update will do fine. > > [...] > > Okay. Your explanation makes sense. > > But here's a real-world example of the problem: > > rrdtool create MadisonSD.rrd --start 937844100 --step 300 \ > DS:input:COUNTER:300:U:U DS:output:COUNTER:300:U:U \ > RRA:AVERAGE:0.5:1:10 > > rrdtool update MadisonSD.rrd -t input:output 937844400:2036007229:1286147890 > rrdtool update MadisonSD.rrd -t input:output 937844700:2051557700:1290492794 > rrdtool update MadisonSD.rrd -t input 937845000:2069078489
You tell rrdtool to update the RRD at 937845000. Only input is known and this automatically defines output to be unknown. At the boundary of the interval you define output to be unknown. The calculation will be: (unknown - 1290492794) / (937845000 - 937844700) == unknown. The problem is that you don't expect to get a PDP for output at this stage while rrdtool is creating one. > rrdtool update MadisonSD.rrd -t output 937845001:1294770454 Here, you are updating output only. Therefore you insert an unknown value for the input. Again, this makes the entire calculation go unknown. > > I think this example demonstrates that asynchronous-DS updates > don't work right. Correct? > IMHO they do what can be expected from them, they do not do what you seem to expect. If this is to be considered a design flaw is yet to be determined. I think it is unfortunate that nobody else responds to this as it is, indeed, something to think about. Right now you are permitted to update the database without specifying all DSes and the missing DSes will be considered unknown. OTOH this is done by using the template function which is, to the best of my knowledge, rather young in comparison to the rest of rrdtool. Perhaps it has to mature. You can get the same behaviour without using the template but you have to specify all DSes then, so you have to fill in the "U". Regards, Alex -- * To unsubscribe from the rrd-developers mailing list, send a message with the subject: unsubscribe to [EMAIL PROTECTED]
