How to differ user activity and system activity in storage operations for warehouse and lakehouses?

Hi Padmanabhan,

Thank you for your inquiry posted on the Microsoft Fabric Community Forum.

Based on my understanding, Fabric does not presently expose OneLake storage level telemetry that explicitly classifies read or write operations as user initiated versus system initiated for Lakehouses or Warehouses. At present, the distinction can only be inferred from workload and activity context.

User activity typically corresponds to identifiable actions such as SQL queries on Warehouses, Spark notebook executions, Dataflow Gen2 runs, pipelines, or semantic model refreshes, whereas system activity comprises background operations such as Delta optimization, metadata synchronization, caching, and internal maintenance, which are not surfaced as individual storage events.

To identify unused Lakehouses or Warehouses, you may review historical read or write trends in the Fabric Capacity Metrics App and verify the absence of notebook runs, pipeline executions, or SQL query activity. Fabric does not currently provide a single “last used” timestamp per item. Further, there is no system table that lists all items in a workspace. Item inventory is accessible through the workspace UI and, for administrators, via the Fabric or Power BI Admin Portal or REST APIs.

For explicit user or system storage attribution, last-used indicators, or centralized inventory views, we would kindly request you to raise a request in the Ideas forum using the link:Fabric Ideas - Microsoft Fabric Community

Additionally, please refer to the links provided below:
What is the Microsoft Fabric Capacity Metrics app? - Microsoft Fabric | Microsoft Learn
Understand the metrics app compute page - Microsoft Fabric | Microsoft Learn
Install the Microsoft Fabric capacity metrics app - Microsoft Fabric | Microsoft Learn
Microsoft Fabric governance - Microsoft Fabric | Microsoft Learn
What is the Microsoft Fabric admin portal? - Microsoft Fabric | Microsoft Learn

We hope the information herein assists in resolving the issue. Should you have any further queries, please feel free to contact the Microsoft Fabric community.

Thank you.

Hello Padmanabhan 

For your use case you should be using OneLake Diagnostics. 

OneLake diagnostics provides end-to-end visibility into how data is accessed and used across your Microsoft Fabric environment. It enables organizations to answer critical questions like "who accessed what, when, and how," supporting data governance, operational insight, and compliance reporting.

OneLake diagnostics - Microsoft Fabric | Microsoft Learn

If you want to check whether a Lakehouse or a Warehouse has not been used for a while, you can use the Capacity Metrics app, that shows the compute consumed by each item. No compute consumed is an indicator it has not been used.