Answer: Scale out the self-hosted integration runtime.

## Detailed Explanation In Azure Data Factory, when a Copy activity involves data movement between different integration runtime types, the execution location follows specific precedence rules. According to Microsoft documentation: - **When source and sink use different integration runtimes**, the copy activity executes on the **self-hosted integration runtime** if either the source or sink is connected to one. ### Analysis of Options: **Option A: Scale out the self-hosted integration runtime** ✅ - **Optimal Choice**: Since Copy1's source is on-premises SQL Server using self-hosted IR, the copy execution occurs on the self-hosted IR. Scaling out (adding more nodes) increases parallel processing capacity and throughput. - **Minimizes Administrative Effort**: Scaling out self-hosted IR involves adding nodes to the existing cluster, which is less administratively intensive than managing Azure infrastructure changes. **Option B: Scale up the data flow runtime of the Azure integration runtime AND scale out the self-hosted integration runtime** ❌ - **Inefficient**: Scaling up Azure IR's data flow runtime is unnecessary since copy activities don't use data flow runtime resources. This adds administrative overhead without performance benefits. - **Violates Minimization Principle**: Combines unnecessary actions, increasing administrative effort. **Option C: Scale up the data flow runtime of the Azure integration runtime** ❌ - **Incorrect Approach**: Copy activities execute on integration runtimes, not data flow runtimes. Scaling data flow runtime has no impact on copy performance. - **No Benefit**: Since the copy executes on self-hosted IR, Azure IR scaling provides zero performance improvement. ### Key Technical Points: 1. **Integration Runtime Selection**: Copy activities use the self-hosted IR when either source or sink requires it. 2. **Self-Hosted IR Scaling**: Scaling out (horizontal scaling) increases parallel data movement capacity. 3. **Administrative Efficiency**: Self-hosted IR scaling requires only node addition to existing infrastructure, aligning with minimal effort requirement. Therefore, scaling out the self-hosted integration runtime directly addresses the compute resource limitation while maintaining minimal administrative overhead.

Author: LeetQuiz Editorial Team