[rrd-users] data resampling Q
scott at PacketPushers.com
Wed Oct 13 22:33:39 MEST 1999
I've noticed some unanticipated behavior in the way rrdtool does
data resampling and wanted to make sure it is working as designed.
I am collecting 5 minute Load Average samples every five minutes.
this is the command i used to create the rrd:
rrdtool create load.rrd DS:la:GAUGE:600:0:U RRA:AVERAGE:0.5:1:384
RRA:AVERAGE:0.5:6:384 RRA:MAX:0.5:6:384 RRA:AVERAGE:0.5:24:384 RRA:MAX:0.5:24:384
So I want to average the averages but always keep the MAX. Now I have
noticed that the true value for the 5 min Load Average is *not* being
recorded in the RRA:AVERAGE:0.5:1:384.
e.g. i put a load average of 111 (it's really LAx100) into the rrd, but it
never got recorded:
# rrtdtool update load.rrd N:111
now, if i think to myself the area of the plot 12,41,81,12 vs 12,111,12,12
i think they are probably the same. so it seems the single sample is
being *averaged* into the RRA somehow, although I just want the 'real'
value of the Load average.
I've even tried RRA:LAST:0.5:1:384. but that seemed to exhibit the same
I understaned the value of the behavior in certain situations, but i would
really just like the data in RRA:AVERAGE:0.5:1:384 to be raw data as
inputed by 'rrdtool update' without any averaging occuring.
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