When a job needs extra power, Fabric lets it briefly run above what its capacity SKU provides so it completes faster; that excess is later smoothed across subsequent timepoints.
Read more: Microsoft Learn
In the Ultra Transcenders books
Each book explains Bursting in context, with comparison tables and the common traps.
Terms in this definition
- Job
A sequence of steps executed together on one agent or runner, or on the server for agentless work. While running, each occupies one of your parallel jobs.
- Capacity
A reserved block of compute for a tenant whose size is fixed by its SKU; Fabric F SKUs express it in capacity units (CUs). Workspaces assigned to it unlock features like Copilot, and from F64 upwards people with free licences can view Power BI content.
- SKU
The size or tier of a service, for example a VM size or the Premium tier of ACR.
Related terms
- Autoscale Billing for Spark
An opt-in way of paying for Spark (Learn also calls it on-demand billing) where jobs use separate serverless compute rather than drawing on the Fabric capacity, and you pay only while jobs are active, capped by a maximum CU setting. Smoothing and bursting play no part, and at the cap new batch jobs wait in a queue while interactive ones are throttled.