[rrd-users] Question regarding missing data points

[Buescher, Friedhelm]

> > Hi,
> >
> > we use rrd to get an overview of our server farm. Every data point
> > that is monitored (disk usage, cpu, mem, temp., iops, bandwidth and so
> > on) gets written to rrd (and then gets visualized via drraw).
> >
> > Every now and then we get some timeout from the monitoring system
> > (read: a missing data point), but i’m unable to implement this in RRD.
> >
> > Minimal compiling sample:
> >
> > ----------------------------------------------------------------------
> > ---------
> > rm test.rrd
> > rrdtool create test.rrd --step 300 --start 1477432800
> > DS:testds:GAUGE:300:U:U RRA:LAST:0:1:10 rrdtool update test.rrd
> > 1477433100:12 rrdtool update test.rrd 1477433400:13 rrdtool update
> > test.rrd 1477433700:15
> > # rrdtool update test.rrd 1477434000:NaN   # here is a missed measuring
> > point
> > rrdtool update test.rrd 1477434300:8
> > rrdtool update test.rrd 1477434600:12
> > ----------------------------------------------------------------------
> > ---------
> >
> > As you can see, the data point for the timestamp 1477434000 will not
> > be written to rrd, but the following data point is available, again.
>
> You are not writing points, you are writing rates which are measured during
> some interval.
> The rate "8" is for time 1477433700..1477434300. This is however not allowed
> because of your heartbeat setting and gets lost.
>
> What happens if you do update at time 1477434000, using value U  ?
>
>

Hi, thanks for the quick Reply!

If i insert the missing value for timestamp 1477434000 with U, everything is OK.

But this is not really the desired (my desired)  behaviour. I'd expect a missing point or rate for one interval to be stored as one missing interval. Not two.

Or am I misunderstood the whole thing?


Best regards,
Friedhelm





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