exactly.....
The uncorrectable ECC is just a sensor instance. Its deasserted and hence the reading is shown as normal(Green) . If ever something fails on the device monitored by this sensor , then the state of this sensor changes to an assert. That is when the reading becomes red and lets you know it is faulty.
So there is nothing to worry about as long as the reading is green. I have seen the same on a variety of hardware.
In order to confirm, do the following steps:
1. Install a WBEM client (wbemcli a command line tool, apt-get wbemcli on ubuntu) on a linux machine.
2. Do a CIM query to CIM_Sensor: Copy the contents to a file:
wbemcli ein -noverify 'https://root:<password>@<hostname>:5989/root/cimv2:CIM_Sensor' ElementName,HealthState | tee SensorList.txt
3. Open SensorList.txt and search for ECC
<snip>
Host:5989/root/cimv2:OMC_DiscreteSensor.DeviceID="201.0.32.1"
-HealthState=5
-ElementName="Memory Device 34 MCK Mem DIMM >16 0: Uncorrectable ECC"
</snip>
4. If the health state above has a value 5 , you have nothing to worry about.