The Problem: Currently, there is no centralized way for a Fabric or Power BI Administrator to extract the offline (compressed disk) size of all semantic models across a tenant. While individual sizes can sometimes be found via the XMLA endpoint or by manually checking the Capacity Metrics App, there is no REST API or Scanner API attribute that exposes this data at scale.
Microsoft has previously noted that this information is not currently exposed in any API. This creates a significant blind spot for administrators who need to:
Manage Capacity Growth: Identify which models are approaching the "Max Offline Dataset Size" limits set in the Admin Portal.
Optimize Costs: Pinpoint bloated models that are consuming excessive storage or will require large memory footprints upon loading.
Proactive Governance: Automate reporting on tenant-wide storage trends to prevent capacity exhaustion before it happens.
The Proposed Solution: Update the Power BI/Fabric Admin REST APIs (specifically the Scanner API or Get Datasets In Group) to include a metadata field for offlineSizeInBytes.
Ideally, this should provide:
The compressed size on disk (Offline Size).
Integration with the Fabric Capacity Metrics App: A dedicated, exportable table showing the size of all items, not just those recently active.
Historical Snapshotting: The ability to see how a model's offline size has grown over time via standard admin logs.
Why this is important for Fabric: As we move toward a more unified Fabric experience, storage and compute are billed and managed more strictly. Knowing the "weight" of a semantic model before it is loaded into memory is a fundamental requirement for any enterprise-grade "Flight Dashboard." We cannot manage what we cannot measure at scale.
