[collectd] Aggregating sensors

[B Martin]

I'm trying to figure out how to aggregate sensor data.  I've tried a 
number of configurations, but I keep getting silent failures (no errors, 
but no data either).  My internet searches have come up empty.  I'm 
hoping someone will tell me where I've gone astray.

I have a farm of blades.  For each blade, I want to collect the 
temperature of the hottest core (e.g. use the aggregation plug-in to 
select the maximum value from amongst all the individual values).  I'm 
currently successfully capturing the temperature of each core 
individually, so the data collection side isn't the issue, it's the 
aggregation.    The data for the individual temperatures is stored as 
$HOSTNAME/sensors-coretemp-isa-0000/temperature-temp$CORE.rrd, where 
$HOSTNAME and $CORE are the name of the host reporting the temperatures 
and the number of the core reporting the temperature, respectively.

Here are some things I've tried:

   <Aggregation>
     Plugin "sensors-coretemp-isa-0000"
     Type "gauge"
     CalculateMaximum true
   </Aggregation>

   <Aggregation>
     Plugin "sensors"
     PluginInstance "sensors-coretemp-isa-0000"
     Type "gauge"
     CalculateMaximum true
   </Aggregation>

   <Aggregation>
     Plugin "sensors"
     PluginInstance "coretemp-isa-0000"
     Type "gauge"
     CalculateMaximum true
   </Aggregation>

   <Aggregation>
     Plugin "sensors"
     Type "gauge"
     CalculateMaximum true
   </Aggregation>

I'm using collectd 5.7.1.

Can someone please put me on the right track?

Thanks to anyone that can help.

          -Brian