<html><body><div><br></div><span style="line-height: 21px; color: rgb(0, 51, 153);">> look for "data resampling" on</span><br style="color: rgb(0, 51, 153);"><span style="line-height: 21px; color: rgb(0, 51, 153);">> http://oss.oetiker.ch/rrdtool/tut/rrdtutorial.en.html</span><div><font color="#003399"><br></font></div><div><font color="#003399">Thank you. The explanation & examples are clear, </font></div><div><font color="#003399">while </font><span style="line-height: 21px; color: rgb(0, 51, 153);">the formula wouldn't be so easy... ;)</span></div><div><span style="line-height: 21px; color: rgb(0, 51, 153);"><br></span></div><div><span style="line-height: 21px; color: rgb(0, 51, 153);">Thank you.</span></div><div><span style="line-height: 21px; color: rgb(0, 51, 153);">jh</span></div><div><span style="line-height: 21px; color: rgb(0, 51, 153);"><br></span></div><p>---------- Původní zpráva ----------<br>Od: Tobias Oetiker <tobi@oetiker.ch><br>Datum: 25. 1. 2013<br>Předmět: Re: [rrd] Re: Re: [rrd-users] How rrdtool will work if there are two or more sample points in one time step</p><br><blockquote>Today j.halifax2@seznam.cz wrote:<br><br>><br>><br>><br>> >rrdtool takes the arrival<br>> >time of the values into account, so unless they are evenly spaced,<br>> >the result will not be the average, but rather an average weighted<br>> >by the interval of the values.<br>><br>><br>><br>> Could you please offer us a formula for calculating a time-step value<br>><br>> of V = f(ti, vi) where ti belong to (t0, tn> for natural n (meaningful).<br>><br>> It would be clearer.<br><br>look for "data resampling" on<br><br>http://oss.oetiker.ch/rrdtool/tut/rrdtutorial.en.html<br><br>for some more detail ..<br><br>rrdtool simply integrates the space underneeth the curve set by the<br>samples and adds a new value at the --step interval so that the<br>space below the new (simpler) curve is the same as with the<br>original sampling data ...<br><br>the curve we are talking here is a simple staire case ... which is<br>ideal for the standard 'counter reading' type input.<br><br>for gauge type samples, one might argue that a different curve<br>might be more apropriate (a linear one for example)<br><br>cheers<br>tobi<br><br><br>><br>><br>><br>><br>> Thank you so much.<br>><br>> jh<br>><br>><br>><br>><br>> ---------- P?vodní zpráva ----------<br>> Od: Tobias Oetiker <tobi@oetiker.ch><br>> Datum: 25. 1. 2013<br>> P?edm?t: Re: [rrd-users] How rrdtool will work if there are two or more<br>> sample points in one time step<br>><br>> "Hi David,<br>><br>> Today David Copperfield wrote:<br>><br>> > Hi,<br>> ><br>> > I am new to wonderful RRD world, and got confused by the<br>> > question:<br>> ><br>> ><br>> > Let's say my rrd file's time step is set 300 seconds, but my<br>> > sample script sends data every 60 seconds and update the rrd file<br>> > 5 times (300/60) in each 60 seconds interval. What the final data<br>> > will show up in the rrd file?<br>> ><br>> > I got bothered by the question, and tried to simulate the case<br>> > but got even more confused.<br>> ><br>> > It turns out that if I run rrdtool update <file> time1:value1<br>> > time2:value2 .... time5:value5 in one command, then I got a<br>> > average of the 5 values (GAUGE type variable for simplicity), but<br>> > if I run 5 'rrdtool update <time:value>' at each interval, then<br>> > the value is of no rules to follow.<br>> ><br>><br>> this works perfectly well ... note that rrdtool takes the arrival<br>> time of the values into account, so unless they are evenly spaced,<br>> the result will not be the average, but rather an average weighted<br>> by the interval of the values.<br>><br>> hth<br>> tobi<br>><br><br>-- <br>Tobi Oetiker, OETIKER+PARTNER AG, Aarweg 15 CH-4600 Olten, Switzerland<br>http://it.oetiker.ch tobi@oetiker.ch ++41 62 775 9902 / sb: -9900</blockquote></body></html>