I believe that RRDtool starts at zero no matter what you say the start is but I might be wrong on that and then calculates buckets based on the step. If your update is not exactly on the step boundry (starting from zero) then your updates will be interpolated. Your updates are between these steps so they are being interpolated. Use dump to look at your raw data.
From: spiderslack [via RRD Mailinglists] [mailto:[email protected]] Sent: Wednesday, June 04, 2014 6:56 PM To: Robert C. Seiwert Subject: [GRAYMAIL] Doubt work rrdtool intervals Hi all. I've been studying the rrdtool tutorial I found very interesting and fantastic. http://oss.oetiker.ch/rrdtool/tut/rrdtutorial.en.html But when trying to play the tutorial with example of my data got the following output. + rrdtool create kakaroto.rrd --start N --step 15 DS:dados:COUNTER:20:U:U RRA:AVERAGE:0.5:1:60 RRA:AVERAGE:0.5:6:5 ++ date +%s + ATUAL=1401916330 + sleep 15 ++ date +%s + rrdtool update kakaroto.rrd 1401916345:2 + sleep 15 ++ date +%s + rrdtool update kakaroto.rrd 1401916360:3 + sleep 15 ++ date +%s + rrdtool update kakaroto.rrd 1401916375:5 + sleep 15 ++ date +%s + rrdtool update kakaroto.rrd 1401916390:7 + sleep 15 ++ date +%s + rrdtool update kakaroto.rrd 1401916405:10 + sleep 15 ++ date +%s + rrdtool update kakaroto.rrd 1401916420:12 + sleep 15 ++ date +%s + rrdtool update kakaroto.rrd 1401916435:15 + sleep 15 ++ date +%s + rrdtool update kakaroto.rrd 1401916450:17 + sleep 15 + rrdtool fetch kakaroto.rrd AVERAGE --start 1401916330 dados 1401916335: -nan 1401916350: -nan 1401916365: 8.8888888889e-02 1401916380: 1.3333333333e-01 1401916395: 1.5555555556e-01 1401916410: 1.7777777778e-01 1401916425: 1.5555555556e-01 1401916440: 1.7777777778e-01 1401916455: -nan 1401916470: -nan See that the values are not entered in the exact period example in period 1401916345 is this between 1401916335 and 1401916350. but I considered it as if it were entered in the period 1401916350 so my reasoning is incorrect readjusting my data would thus 1401916335: -nan 1401916350: 2 1401916365: 3 1401916380: 5 1401916395: 7 1401916410: 10 1401916425: 12 1401916440: 15 1401916455: 17 1401916470: -nan Doing the calculations according to the example of the tutorial http://oss.oetiker.ch/rrdtool/tut/rrdtutorial.en.html Using octave octave:32> abs(2-3)/15 ans = 6.66666666666667E-02 octave:33> abs(3-5)/15 ans = 1.33333333333333E-01 octave:34> abs(5-7)/15 ans = 1.33333333333333E-01 octave:35> abs(7-10)/15 ans = 2.00000000000000E-01 octave:36> abs(10-12)/15 ans = 1.33333333333333E-01 octave:37> abs(12-15)/15 ans = 2.00000000000000E-01 octave:38> abs(15-17)/15 ans = 1.33333333333333E-01 octave:39> See that the values are different where I am going wrong? thank you Regards _______________________________________________ rrd-users mailing list [hidden email]</user/SendEmail.jtp?type=node&node=7582142&i=0> https://lists.oetiker.ch/cgi-bin/listinfo/rrd-users ________________________________ If you reply to this email, your message will be added to the discussion below: http://rrd-mailinglists.937164.n2.nabble.com/Doubt-work-rrdtool-intervals-tp7582142.html To start a new topic under RRDtool Users Mailinglist, email [email protected]<mailto:[email protected]> To unsubscribe from RRD Mailinglists, click here<http://rrd-mailinglists.937164.n2.nabble.com/template/NamlServlet.jtp?macro=unsubscribe_by_code&node=937164&code=cm9iQHZjYS5jb218OTM3MTY0fC0xMzA5NDI1MzI4>. NAML<http://rrd-mailinglists.937164.n2.nabble.com/template/NamlServlet.jtp?macro=macro_viewer&id=instant_html%21nabble%3Aemail.naml&base=nabble.naml.namespaces.BasicNamespace-nabble.view.web.template.NabbleNamespace-nabble.naml.namespaces.BasicNamespace-nabble.view.web.template.NabbleNamespace-nabble.naml.namespaces.BasicNamespace-nabble.view.web.template.NabbleNamespace-nabble.naml.namespaces.BasicNamespace-nabble.view.web.template.NabbleNamespace-nabble.view.web.template.NodeNamespace&breadcrumbs=notify_subscribers%21nabble%3Aemail.naml-instant_emails%21nabble%3Aemail.naml-send_instant_email%21nabble%3Aemail.naml> -- View this message in context: http://rrd-mailinglists.937164.n2.nabble.com/Doubt-work-rrdtool-intervals-tp7582142p7582143.html Sent from the RRDtool Users Mailinglist mailing list archive at Nabble.com. _______________________________________________ rrd-users mailing list [email protected] https://lists.oetiker.ch/cgi-bin/listinfo/rrd-users
