Hi Denis, On Thu, Sep 09, 2010 at 07:52:07PM +0400, Denis Melnikov wrote: > Now if I see for example 783.3 on my graph I believe I can see " 200 > resp=783.3" in the logfile. But I don't see it! Instead, I find " 200 > resp=1537.387".
I believe this is due to the way RRDtool builds the "Primary Data Point" (PDP). It basically comes down to this: RRDtool uses fixed intervals. If you use a ten second step, for example, these intervals would start at t=0, t=10, ..., t=1284049090, t=1284049100, ... and last for ten seconds each. If you add an update to RRDtool at an arbitrary point in time, say value[t=17]=200 value[t=27]=1000 value[t=37]=100 then the value for PDP[t=20] will be calculated from the values t=17 and t=27 as PDP[20] = 7/10 * value[17] + 3/10 * value[27] = 140 + 300 = 440 PDP[30] = 7/10 * value[27] + 3/10 * value[37] = 700 + 30 = 730 So the problem is that the "Consolidation Function" (CF) is not taken into account when building a PDP -- only to create "Consolidated Data Points" (CDP). > `rrdtool fetch` lists as follows: > > 1284033470: 2.4634500000e+01 > 1284033480: 7.8328150000e+02 > 1284033490: 7.7944550000e+02 > 1284033500: 1.9102000000e+01 This output supports the argument given above: The value (1537.387) was apparently distributed over two PDPs: 7.8328150000e+02 + 7.7944550000e+02 = 1562.727 > Is it possible? With RRDtool, no. Not that I'm aware, anyway. You could use the "CSV" plugin, for example. That doesn't do any of that magic and will store 1537.387 as you'd expect. > Otherwise, what is a benefit of GaugeMax? If within one interval *multiple* lines are matched by the regular expression, only that value will be passed on to the write plugins. As long as the value is within collectd, it *is* 1537.387. The unintended averaging happens after the value has left collectd's control. Hope this helps.. Regards, --octo -- Florian octo Forster Hacker in training GnuPG: 0x0C705A15 http://octo.it/
signature.asc
Description: Digital signature
_______________________________________________ collectd mailing list collectd@verplant.org http://mailman.verplant.org/listinfo/collectd
