Thank you @Sander van de Velde for your feedback on this post.
@Michael Skaaning Kristensen I appreciate your investigation on this issue and figuring out what is contributing towards the increased number of messages on the IoT Hub. I am providing your observations below to help other community members figure out one of the possible reasons for the message count increase.
Issue: Total number of messages used
The total number of messages count on IoT Hub increased drastically.
Cuase
Further analysis on Diagnostic logs revealed that Device to Cloud File upload has increased which contributed to the increased number of messages.
Device to Cloud file upload messages also contribute towards the total number of messages in Azure IoT Hub. When a device uploads a file to IoT Hub, it is treated as a message and counted towards the message quota for the IoT Hub.
It's worth noting that the size of the uploaded file can affect the number of messages that are counted towards the quota. For example, if a device uploads a large file, it may be split into multiple messages, each of which will count towards the message quota. Here is a reference to the Throttling limits
I cannot get a view of this device to cloud file upload in the metrics section.
There is no out of the box view provided on IoT Hub to monitor/track the file uploads. If you files are being routed to a same blob storage end point, you can create a view on the storage container and keep track on the total transactions on the end point such as below.
Hope this helps! I appreciate it if you can click Accept Answer and Yes for the answer provided. Doing so would help other community members with similar issue identify the solution. I highly appreciate your contribution to the community.
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