You can monitor thresholds from the Manager Dashboard pages.
Task
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Click the numbers listed against the device to be monitored under the warnings column of the
System Faults monitor.
System Faults monitor 
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The
Faults tab in the
Logs page displays the list of warnings for the selected device.
The warnings relating to the Sensor performance monitoring thresholds are listed as a Device Performance - Memory Usage - System Memory fault type.
Warning dialog 