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I'm seeing a Azure IoT project that involves IoT Hub and IoT edge custom modules behind a gateway (nested IoT architecture). Some custom modules have a big configuration file to define the acquiring the signals of thousands tags.

I found out the synchronization between IoT Hub and IoT Edge modules can be managed through Module TWINS (JSON document) inserting tags definition in properties.desired json object

By Microsoft documentation (link):

Desired properties. Used along with reported properties to synchronize module configuration or conditions. The solution back end can set desired properties, and the module app can read them. The module app can also receive notifications of changes in the desired properties.

As written at the beginning, unfortunately my use case has a configuration file that defines all tags about 10 MB

By Microsoft documentation exists the followed size limit for desired properties:

Module twin size IoT Hub enforces an 8 KB size limit on the value of tags, and a 32 KB size limit each on the value of properties/desired and properties/reported.

I found a workaround suggested from Microsoft

Link

High Level Solution

I'd like to know if this solution also works with Edge module behind a gateway.

Thanks

Stefano
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  • hope this [helps](https://learn.microsoft.com/en-us/azure/iot-hub/module-twins-dotnet) – Sampath Jul 05 '23 at 03:13
  • for desired properties refer [this](https://stackoverflow.com/questions/76173024/exception-in-reading-list-of-azure-iot-devices-in-c-sharp-azure-function/76181345#76181345) – Sampath Jul 05 '23 at 03:17
  • Hi @Sampath, thanks for the shared links. But the module Twins has properties.desired content limited to 32 KB. When properties.desired's JSON content exceed the limit, you need to use the workaround as suggests Microsoft in the last link written in my post. Does workaround work on IoT Edge behind a gateway (nested architecture - parent and child) ? – Stefano Jul 05 '23 at 07:24
  • I also raised this limitation at the followed link: https://learn.microsoft.com/en-us/answers/questions/1327919/which-is-the-recommended-way-by-microsoft-to-deplo – Stefano Jul 11 '23 at 13:12
  • refer this IoT Edge behind a [gateway](https://learn.microsoft.com/en-us/azure/iot-edge/iot-edge-as-gateway?view=iotedge-1.4) – Sampath Jul 18 '23 at 14:22
  • Yes, workarounds can be implemented on IoT Edge behind a gateway in a nested architecture (parent and child). – Sampath Aug 02 '23 at 22:34

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