[rrd-users] RRD Not Storing Historical Gauge Data

William R. Lorenz wrl at express.org
Tue Nov 4 16:09:47 CET 2008

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.

William R. Lorenz

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