[rrd-users] Unexplained NaN's All over the show...

[Andrew Kempe]

I've been attempting to input 286 readings into an rrd database but keep
getting unexplained NaN all over the show.

My data is the amount of data output by a device. The amount is read every
300 seconds and written to a file. The readings are timestamped in multiples
of 300 - meaing the timestamps are always valid and exactly 300 seconds
apart. The counter of the device is then reset to 0 after each reading.

So I could have values as follows:

10
20
15
30
12

My rrd is created in the following way:

rrdtool create C:\rrdtool\test.rrd --start 982324800 \
--step 300 DS:bitsIn:GAUGE:600:0:U \
RRA:AVERAGE:0.5:1:286

I then proceed to update the rrd with the following data:

982325100:5634420
982325400:5639330
982325700:5833740
982326000:5903560
.
.
.
982411200:708887

My timestamps are exactly 300 seconds apart. Every single reading has a
valid timestamp - so there should never be an invalid reading - atleast not
due to an invalid timestamp.

Yet when you dump the rrd to xml, there are rows with NaN in them. Eg:

<!-- 2001-02-16 20:45:00 South Africa Standard Time --> 
	<row><v> 1.9884600000e+006 </v></row>
<!-- 2001-02-16 20:50:00 South Africa Standard Time --> 
	<row><v> NaN </v></row>
<!-- 2001-02-16 20:55:00 South Africa Standard Time --> 
	<row><v> NaN </v></row>
<!-- 2001-02-16 21:00:00 South Africa Standard Time --> 
	<row><v> NaN </v></row>
<!-- 2001-02-16 21:05:00 South Africa Standard Time --> 
	<row><v> 2.2503400000e+006 </v></row>

I can't seem to see why the data being input is invalid. Am I doing
something wrong when it comes to creating the database? I've tried creating
the rrd as a GUAGE, ABSOLUTE, COUNTER etc etc but I still get these invalid
entries. I've even tried writing a simple application that has two counters,
one for time and one for a value. They are incremented by 300 and 1
respectively. So the data is totally symetrical. Yet when I upate the rrd it
continues to have NaN's all over the show.

Any help would be appreciated!!

Thanks, Andrew

--
Unsubscribe mailto:rrd-users-request at list.ee.ethz.ch?subject=unsubscribe
Help        mailto:rrd-users-request at list.ee.ethz.ch?subject=help
Archive     http://www.ee.ethz.ch/~slist/rrd-users
WebAdmin    http://www.ee.ethz.ch/~slist/lsg2.cgi