We’re experiencing critical timeout errors with device shadow ingestion in our aziot-25 deployment. Our industrial IoT devices send shadow updates every 30 seconds, but about 40% of updates fail with timeout errors after 15 seconds. The shadow ingestion pipeline worked fine in aziot-24, but after upgrading we’re seeing these failures.
The timeout occurs during shadow state synchronization, and we suspect firmware compatibility issues with the new SDK version. We’ve implemented basic retry logic, but it’s not handling the timeouts effectively:
{
"error": "RequestTimeout",
"message": "Shadow update exceeded 15s limit",
"deviceId": "sensor-floor-3-012"
}
This impacts real-time monitoring of 200+ production devices. Has anyone solved shadow ingestion timeouts in aziot-25? Need guidance on retry strategies and firmware compatibility checks.
Have you configured the shadow ingestion retry policy correctly? The default exponential backoff in aziot-25 starts at 2s with a 2x multiplier, maxing at 30s. For high-frequency updates like yours (every 30s), you need a more aggressive policy. We use 1s initial delay with 1.5x multiplier and it works better for near-real-time scenarios.
Check your Event Hub throughput units and partition strategy. Shadow ingestion in aziot-25 is more sensitive to backend throttling. If your Event Hub is undersized, you’ll see timeout cascades even with good device firmware. We had to scale from 2 to 5 throughput units after our upgrade to handle the same device load. Monitor the IncomingRequests and ThrottledRequests metrics in Azure Monitor.
Don’t increase the timeout - that’s treating the symptom. The 15s limit is there for good reason. Instead, optimize your shadow payload by sending only changed properties (delta updates) rather than full shadow documents. We reduced our average payload from 8KB to 1.2KB and shadow ingestion times dropped from 20s to 4s. Also implement proper connection pooling in your device code to avoid connection overhead on each update.
Thanks for the insights. I checked our Event Hub metrics and we’re hitting throttling limits during peak hours (8am-10am). Our firmware is v2.3.1 which should be compatible with aziot-25 according to the compatibility matrix. The 15s timeout threshold explains why we’re seeing failures - our devices on slower networks take 18-22 seconds for shadow updates. Should we increase the timeout or optimize the payload size?
I’ve seen similar timeout issues after aziot-25 upgrades. First check is your device firmware version compatibility with the new SDK. The shadow ingestion timeout threshold changed from 30s to 15s in aziot-25, which catches slower devices. Also verify your retry logic includes exponential backoff - simple retries can make timeouts worse by flooding the ingestion pipeline during peak loads.