Analysis of the Question Requirements

The question requires a solution that:

1. Incrementally copies only new or modified blobs from Azure Blob Storage account1 to account2
2. Minimizes development effort for pipeline creation
3. Uses scheduled intervals for replication

Evaluation of Options

Option D: Run the Copy Data tool and select Built-in copy task ✅

• Optimal Choice: The Built-in copy task in Azure Data Factory's Copy Data tool provides a guided, wizard-based approach specifically designed for incremental copy scenarios using LastModifiedDate.
• Incremental Copy Support: It automatically handles incremental loading by tracking the last modified timestamp of files, ensuring only new or modified blobs are copied in subsequent runs.
• Minimal Effort: This is a no-code/low-code solution that requires minimal development effort - users simply configure source, destination, and scheduling through an intuitive interface.
• Scheduling Integration: The tool automatically creates a pipeline with trigger scheduling capabilities.
• Official Microsoft Documentation: Microsoft's official tutorial for incremental copy using LastModifiedDate specifically recommends this approach.

Option A: Run the Copy Data tool and select Metadata-driven copy task ❌

• Overkill for Simple Scenario: Metadata-driven copy is designed for complex scenarios involving thousands of tables or objects across multiple sources and destinations.
• Higher Complexity: Requires creating and managing external control tables, parameterized pipelines, and metadata configurations.
• Not Minimal Effort: This approach requires significantly more setup and configuration compared to the built-in copy task.

Option B: Create a pipeline that contains a Data Flow activity ❌

• Unnecessary Complexity: Data Flow activities are designed for data transformation, not simple replication scenarios.
• Higher Development Effort: Requires building and configuring data flows, which is excessive for a basic blob replication task.
• Not Optimized for Incremental Copy: While possible, this requires manual implementation of incremental logic.

Option C: Create a pipeline that contains a flowlet ❌

• Inappropriate Tool: Flowlets are reusable data flow components for transformation logic, not for data movement between storage accounts.
• Does Not Address Requirements: Flowlets don't provide built-in incremental copy capabilities or minimize development effort.

Why Option D is the Optimal Choice

The Built-in copy task directly addresses both requirements:

1. Incremental Copy: It uses the LastModifiedDate property of blobs to automatically detect and copy only new or modified files since the last pipeline run.
2. Minimal Effort: The Copy Data tool provides a complete wizard that handles pipeline creation, source/destination configuration, incremental settings, and scheduling with minimal manual intervention.

This approach represents the most efficient and appropriate solution for the described scenario, aligning with Azure Data Factory best practices for simple incremental data movement between storage accounts.