Preventing ThrottlingException in Azure IoT Hub for NH3 Monitoring
Question
You are operating an industrial IoT infrastructure solution of a chemical plant with sensors to monitor possible NH3 contamination in the air.
The telemetry data from the sensors are sent to an IoT Hub.
While sending messages to the IoT Hub, in certain periods of the day, devices receive 429 ThrottlingException from the IoT Hub which projects the risk of data loss.
What would you do to stop this behavior?
Answers
Explanations
Click on the arrows to vote for the correct answer
A. B. C. D.Correct Answer: C.
Option A is incorrect because IoT Hub's ability to manage violations of throttling threshold is limited.
Investigation of the causes is needed.
Option B is incorrect because “traffic shaping” is an internal mechanism of the IoT Hub to buffer temporary, short bursts in the D2C traffic.
Size of the buffer is not customizable.
Option C is CORRECT because the error message shows that you are reaching the throttling limit.You should first check your Telemetry message send attempts metric against the throttling limits for the tier and edition of your IoT hub.
Option D is incorrect because while IoT Hub is prepared to manage burst traffic to some extent, message 429 shows that extreme rate of traffic has been continuing for a longer period.
You should investigate device-to-cloud traffic metrics in order to prevent loss of messages.
References:
The correct answer to this question is C: Check Telemetry message send attempts metric; revise the send message rate of device.
Explanation:
In the given scenario, the devices sending telemetry data to the IoT Hub are receiving 429 ThrottlingException errors, indicating that the IoT Hub is unable to handle the incoming traffic due to high message send rate. This could result in data loss, which is undesirable.
To resolve this issue, it is important to understand the root cause of the problem. One way to do this is to check the Telemetry message send attempts metric, which provides insights into the number of attempts made by the device to send messages to the IoT Hub. This metric can be viewed in the Azure portal or using the Azure CLI.
Once the metric is analyzed, it is necessary to revise the send message rate of the device, which may involve reducing the message frequency or batching multiple messages into a single request. This will help to reduce the load on the IoT Hub and prevent it from getting overwhelmed.
Option A, "It's only a warning. No action is needed because IoT Hub will manage it automatically" is incorrect, as the ThrottlingException indicates that there is a problem that needs to be addressed to prevent data loss.
Option B, "Increase the size of the traffic shaping queue to prevent the problem" is also incorrect, as this may only delay the problem but not prevent it from happening. It may also consume more resources and increase latency.
Option D, "IoT Hub's traffic shaping will smooth the traffic. No action is needed" is incorrect, as while IoT Hub's traffic shaping feature can help to smooth the traffic, it may not be enough to handle the high message send rate in this scenario.
