RRD Files No valid data

[milesb]

After the network that I monitor went laggy causing snmpwalks to take abbsolutely ages, Weathermap has stopped graphing properly. In the poller output I get these arrors for every link -

06/21/2007 11:47:34 AM - WEATHERMAP: Poller[0] ReadData: Link m320-7401, target: /usr/share/cacti/rra/lancaster_m320_traffic_in_22.rrd on config line 51 had no valid data

[milesb]

I've dumped some of the rrd files to plain ASCII. Some of the lines that Weathermap complains about are below:

<!-- 2007-06-19 21:20:00 BST / 1182284400 --> <row><v> NaN </v><v> 4.1906497461e+04 </v></row>

<!-- 2007-06-19 21:55:00 BST / 1182286500 --> <row><v> NaN </v><v> 1.5745682980e+05 </v></row>

<!-- 2007-06-19 21:35:00 BST / 1182285300 --> <row><v> NaN </v><v> 6.0630950804e+05 </v></row>

[Howie]

<!-- 2007-06-19 21:35:00 BST / 1182285300 --> <row><v> NaN </v><v> 6.0630950804e+05 </v></row>

It's looking for a row with valid data in each column. These rows only have valid data in one column. This is a problem with your cacti really, IMHO. Presumably your cacti graphs are showing NaNs as well?