Data Factory runtime is busy error when mirroring tables from on-prem SQL Server on Trial capacity

Hey hemanthsmg , 

This error is happening because mirroring from on-prem SQL Server to Fabric uses Data Factory Integration Runtime (IR) behind the scenes, and in Trial capacity the compute allocated to Data Factory is very limited and shared. When it says “Data Factory runtime is busy”, it usually means the managed Integration Runtime assigned to your workspace does not have available capacity to spin up the connection test or replication pipeline.

In Trial capacity, this can persist for hours because resources are throttled and shared across many tenants. So even if you retry later, the backend runtime may still not allocate compute.

Here are the practical things you can check and try:

First, confirm whether you are using a Self-hosted Integration Runtime installed on-prem. For on-prem SQL Server mirroring, you must install and register a Self-hosted IR on a local machine that has access to the SQL Server. If you are relying only on the default managed runtime, connection tests will fail.

Second, verify the Self-hosted IR status:

• Go to Fabric → Data Factory → Manage connections → Integration runtimes
• Ensure the runtime shows Online
• Check that it is not overloaded (CPU/memory on that server)

Third, Trial capacity has strict limits on:

• Parallel activities
• Compute allocation
• Data movement throughput

If multiple pipelines, notebooks, or test attempts are running, they may consume the limited runtime slots. Stop any other Fabric activities and retry.

Fourth, reduce the load:

• Try mirroring only one small table first
• Disable “Automatically mirror future tables”
• Avoid selecting many large tables during initial test

If even a single small table fails with the same runtime busy error, then it is almost certainly Trial capacity throttling.

The most reliable solution in this scenario is upgrading to a paid Fabric capacity (F SKU). Trial environments are not designed for sustained mirroring workloads, especially from on-prem sources.

As a workaround under Trial:

• Use Dataflow Gen2 to copy a small dataset first
• Or manually test connection via Data Factory pipeline before enabling mirroring
• Restart the Self-hosted Integration Runtime service

In summary, this is typically not a SQL Server issue. It is a capacity/runtime allocation limitation in Trial Fabric. If the error persists for hours even for small tables and the Self-hosted IR is healthy, upgrading capacity is usually the only stable resolution.

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Thanks for being part of the discussion!