Intermittent issue: Poller shows no valid data

[ds20prefecture]

I have 4 active maps, total number of nodes is 879.
123Switches - 426 nodes - all except 8 are NINKs
cp-core - 373 nodes - all except 7 are NINKs
123interconnects - 19 nodes
iWan - 61 nodes

Strange error whereby I have no errors on maps until I added cp-core. All maps were showing clear, and all nodes in 123Switches.conf were displaying without error in the poller. When I add a the cp-core map, all maps show errors. If I remove cp-core again the other map's errors clear.

I assume it is to do with load, so upped the poller threads per process from 1 to 3, but no effect. Do I need to beef up the machine it runs on? It's a VM with one vCPU and 2GB of RAM running RHEL5 and Cacti 0.8.8b with Weathermap 0.98

06/28/2017 09:21:40 AM - WEATHERMAP: Poller[0] WARNING: [Map 9] 123Switches.conf: ReadData: NODE lan_sw10-Fa47, target: /home/www/cacti/rra/58/2730.rrd on config line 3032 of /home/www/cacti/plugins/weathermap/configs/123Switches.conf had no valid data, according to WeatherMapDataSource_rrd
06/28/2017 09:26:47 AM - WEATHERMAP: Poller[0] WARNING: [Map 9] 123Switches.conf: ReadData: NODE lan_sw02-Fa02, target: /home/www/cacti/rra/30/960.rrd on config line 72 of /home/www/cacti/plugins/weathermap/configs/123Switches.conf had no valid data, according to WeatherMapDataSource_rrd

[rony]

Who is your polling times? Are you having poller overruns (when the poller takes longer than the interval to run)?

[ds20prefecture]

POller is 1 minute. I'll bet you're right. Will adjust to 5 and see

[ds20prefecture]

That solved it, thanks for your help