> Let me elaborate on this: > > > rrdtool update test.rrd 1477433700:15 > > # rrdtool update test.rrd 1477434000:NaN # here is a missed measuring > > point > > rrdtool update test.rrd 1477434300:8 > > > Can anyone advise how to setup the rrd, so that one missing PDP gets > > exactly one NaN ? > > The problem is that you get 2, not 1, unknown PDPs. That is because the > update at timestamp 1477434300 will fill all the time between the last update > (1477433700) and itself. The rate is unknown because of your heartbeat > settings. > > As far as I know you cannot do something in RRDtool to say that updates are > for 300 seconds only and if there is more time not updated, it should be > processed as if it was updated with U. But who knows, maybe I'm missing > something. > > Unless someone else comes up with a better solution, you will have to > update using U (for unknown) or accept that one more PDP will also be > unknown. If the monitoring is offline for e.g. 55 minutes, the next update > will try to fill 12 PDPs which will all be unknown. > > A quick hack, if you can spare the resources, is to update 300 seconds ago > with rate U and just ignore the error RRDtool will give you if that update was > already successfully done. > > A less quick hack is to modify your scripts so that it remembers the last > update time (or queries it from the RRD) and looks at the difference with > now. If that is more than 300 seconds, then update with rate U and time > now-300s. > Yes, i implemented the last approach and it worked as expected:
Everytime I get a new value to update, I ask the rrd to for the last timestamp (rrd->last). If this timestamp is older than $now -monitoring_intervall, I update the timestamp $now - $monitoring_intervall with U. After that, I update $now with the current value. This gives exactly one missing block in RRD as expected. Thanks for your support in thinking! Best regards, Friedhelm CEWE Stiftung & Co. KGaA mit Sitz in Oldenburg; Registergericht Oldenburg HR B 208214; Persönlich haftende geschäftsführende und vertretungsberechtigte Gesellschafterin: Neumüller CEWE COLOR Stiftung, Sitz: Oldenburg; Stiftungsverzeichnis der rechtsfähigen Stiftungen des bürgerlichen Rechts im Bezirk der Regierungsvertretung Oldenburg Nummer 15(034). Stiftungsvorstand: Dr. Rolf Hollander (Vorsitzender), Patrick Berkhouwer, Dr. Reiner Fageth, Dr. Christian Friege, Carsten Heitkamp, Dr. Olaf Holzkämper, Thomas Mehls, Frank Zweigle Aufsichtsrat: Otto Korte (Vorsitzender) UST ID-Nr. DE815453806; St.-Nr. 64/200/38999; GLN 40 04468 00000 4 _______________________________________________ rrd-users mailing list rrd-users@lists.oetiker.ch https://lists.oetiker.ch/cgi-bin/listinfo/rrd-users
