[rrd-users] RRD Not Storing Historical Gauge Data
rrd-users at ficos.de
Tue Nov 4 18:16:47 CET 2008
William R. Lorenz wrote:
> Hi All,
> I'm trying to create a GAUGE-like RRD, fill it with historical data, and
> then graph the results. Unfortunately, my graph simply returns NaNs, with
> `rrdtool dump <file>` returning the same -- no useful data. My hope is
> that someone will spot an obvious flaw and may be able to help with this.
> rrdtool create host_1.rrd \
> --start 1225580613 -s 60 \
> DS:min:GAUGE:120:U:U \
> DS:avg:GAUGE:120:U:U \
> DS:max:GAUGE:120:U:U \
> DS:dev:GAUGE:120:U:U \
> DS:avl:GAUGE:120:U:U \
> RRA:AVERAGE:0.5:1:576 \
> RRA:AVERAGE:0.5:6:672 \
> RRA:AVERAGE:0.5:24:732 \
> RRA:AVERAGE:0.5:144:1460 \
> RRA:MIN:0.5:1:576 \
> RRA:MIN:0.5:6:672 \
> RRA:MIN:0.5:24:732 \
> RRA:MIN:0.5:144:1460 \
> RRA:MAX:0.5:1:576 \
> RRA:MAX:0.5:6:672 \
> RRA:MAX:0.5:24:732 \
> rrdtool update host_1.rrd 1225580613:161.429:163.724:167.428:2.055:100
> rrdtool update host_1.rrd 1225581006:159.928:161.264:163.551:1.513:100
> rrdtool update host_1.rrd 1225581366:160.575:163.766:165.816:1.926:100
> rrdtool update host_1.rrd 1225582026:159.407:161.301:163.695:1.926:100
> rrdtool update host_1.rrd 1225582686:159.901:161.596:164.051:1.879:100
> rrdtool update host_1.rrd 1225583106:159.436:161.427:164.972:2.233:100
> While I find only NaN entries in the graph and via `rrdtool dump`, the
> `rrdtool info` command returns at least a last_ds which seems reasonable:
> ds[min].type = "GAUGE"
> ds[min].minimal_heartbeat = 120
> ds[min].last_ds = "159.436"
> ds[min].unknown_sec = 6
> Because this is historical data, could this be a problem with rrdtool
> checking the system clock when inserting gauge data into the RRD file?
> Thanks, in advance, for any insights.
you have defined a heartbeat of 120, but your datapoint are much more than 120s
apart which results in NaN - perfectly valid.
Try to increase your heartbeat to a value large enough for the biggest step between
your datapoints, e.g. 1200 or larger - that'll make it work.
rrdtool create host_1.rrd \
--start 1225580613 -s 60 \
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