MQTT Buffer overflow alarm

[Mahmoud_Sayed]

Issue

MQTT data points are no longer published to MQTT broker with "MQTT - Buffer overflow" alarm.

System alarm: Buffer overflow - Not all MQTT messages have been sent

Product Line

EcoStruxure Building Operation

Environment

• Building Operation Automation Server Premium
• Building Operation Automation Server Bundled
• Building Operation Enterprise Server

Cause

Long MQTT queue can be caused by, too many variables define in MQTT data groups, fast publishing, i.e. low interval or low delta value, Low CPU and RAM resources, or slow network.

Resolution

Once MQTT Buffer overflow alarm is generated, the below configuration shall be checked:

1. Data points interval value, if the interval is enabled, make sure it is not a very low interval.
2. Data points delta value, for event driven, make it is not very low value, especially for fast changing variables.
3. Review the network performance.
4. Make sure that the EBO server has sufficient CPU and RAM resources, and check Architectural guidelines for the effect of the Number of MQTT Data Points on the CPU Load. For Automation Server, the system memory usage should never exceed 80% and CPU usage should stay below 60%.