Azure IoT Hub: What would happens to Iot hub messages if daily message limit is exceeded?

Question

Hello Everybody, I have a question about IoT hub messages.
What would happen to the IoT hub messages if the messages count exceeds the daily limit?
What do you recommend to debug IoT hub messages?
Thanks!

Answer 1

Hi,

If you do hit the limit, IoT Hub responds with error code 429 and the client should back-off and retry. These limits are per hub (or in some cases per hub/unit).

Also, the device should be disconnected and the Send and Receive operations are blocked for your IoT Hub until the next day.

If you are using the https protocol, the following response will be sent by Azure IOT Hub:

{  
  "Message": "{\"errorCode\":403002,\"trackingId\":\"c41eb2xxxxx3fxxxce-G:3-TimeStamp:12/12/2019 12:36:43\",\"message\":\"Total number of messages on IotHub 'xxxxxxxxx' exceeded the allocated quota. Max allowed message count : '8000', current message count : '8448'. Send and Receive operations are blocked for this hub until the next UTC day. Consider increasing the units for this hub to increase the quota.\",\"timestampUtc\":\"2019-12-12T12:36:43.5570129Z\"}",  
  "ExceptionMessage": ""  
}  

The tier and number of units determine the maximum daily quota of messages that you can send. Please see IoT Hub quotas and throttling for more details.

At any given time, you can increase quotas or throttle limits by increasing the number of provisioned units in an IoT hub.

IoT Hub metrics give you better data about the state of the Azure IoT resources in your Azure subscription. IoT Hub metrics enable you to assess the overall health of the IoT Hub service and the devices connected to it. Please refer Understand IoT Hub metrics for more details.

You can also monitor the messages using Azure IoT Hub Toolkit extension for Visual Studio Code, Device Explorer and Azure CLI IoT Extension.

Hope this helps.