Limit on get request (Admin - Datasets GetDatasourcesAsAdmin)

With 11,000 datasets, you have definitely moved past the "standard" Admin APIs limit.

The  GetDatasourcesAsAdmin explicitly states a limit of 300 requests per hour.

The Solution: The Scanner API (Metadata Scanning)

For a tenant of your size, you should switch to the Scanner API. It is designed specifically to handle metadata for up to 10,000+ workspaces efficiently.

Even I use the Scanner APIs to scan our entire tenant, since we also have a large tenant with more than 17k reports and more than 10k datasets.

Microsoft calls this Metadata Scanning. Refer to the link - https://learn.microsoft.com/en-us/fabric/governance/metadata-scanning-overview for detailed steps, I have tried to give a brief oveview below - 

Unlike the standard "Loop and Fetch" method, the Scanner API is asynchronous and works in four stages:

1. Get Modified Workspaces: Call admin/workspaces/modified. This gives you a list of workspace IDs that have changed (or all of them if it's your first run).

2. Trigger the Scan: Call admin/workspaces/getInfo. You post a list of Workspace IDs (in batches of 100). This returns a ScanID.

3. Check Status: Poll admin/workspaces/scanStatus/{ScanID} until it says "Succeeded."

4. Get the Result: Call admin/workspaces/scanResult/{ScanID}. This returns a massive JSON containing everything: datasets, tables, and—crucially for you—the Datasource details.

I would also recommend referring to Rui Ramano's awesome Power BI Monitor Solution that makes use of Scanner APIs for Admin Monitoring - https://github.com/RuiRomano/pbimonitor

Let me know if this helps or if you need anything else!

Thanks & Regards,

Bipin