Storage trigger event

Hey fabricpribeiro,

Your are already aware of the topic pretty well. But just so it helps others, I will try to answer your questions directly.

Q1 - Is your undertanding correct? and is this doable for fabric data factory pipelines?  

Yes. OneLake events are notifications triggered by changes within the data lake (creation/modification/deletion of files and folders). There is no constant watching happening. OneLake itself fires the event, and the pipeline only wakes up when that event arrives.

The exact flow under the hood is: OneLake --> emits event --> Activator receives it --> triggers the pipeline.

Q2 - This trigger type (storage) is in public preview or in GA?

GA. Azure and Fabric Events (which includes OneLake events) are Generally Available. This was announced in April 2025.

Q3 - Will it be expensive because it keeps watching?

No cost for watching. The architecture is push-based, not polling. So you only pay for pipeline runs when a file actually lands, not for idle watching time. Your teammates' concern doesn't apply here.

And I think, by now, you would have convinced your team😉

Hi fabricpribeiro,

Based on our understanding, there is no charge for monitoring a folder, as processing occurs only when an event is triggered. Given your workload, approximately 60 small files per month on F16, the impact is negligible.

Additionally, you do not need to create or manage any Eventhouse. Microsoft Fabric automatically provisions the required event infrastructure in a fully managed, serverless manner, without idle compute costs.

Additionally, kindly refer to the links below:
Fabric OneLake Events in Fabric Real-Time Hub - Microsoft Fabric | Microsoft Learn
Activator capacity consumption, usage reporting, and billing - Microsoft Fabric | Microsoft Learn

We hope the above information resolves the issue. Should you have any further queries, please feel free to contact the Microsoft Fabric community.

Thank you.