Agile methodology promotes the Agile Manifesto to ensure early and continuous delivery of valuable ETL testing outcomes. The Agile Manifesto emphasizes customer collaboration, responding to change, and delivering working solutions iteratively.

To ensure data quality in integrating data from multiple sources, ETL testing best practices include Data Profiling, Metadata Verification, Cross-System Validation, and Volume Testing. Data profiling helps understand the characteristics of data, while cross-system validation ensures consistency across different sources.

Agile methodology addresses evolving data schemas through Dynamic Schema Evolution. This approach allows for seamless adaptation to changing data structures, ensuring compatibility and accuracy in ETL processes.

The growing trend of Big Data is expected to offer new challenges and opportunities in ETL testing. As organizations deal with larger and more diverse datasets, ETL testing strategies must adapt to handle the complexities of Big Data processing.

A modern Data Warehouse commonly employs a Three-tier architecture. This architecture consists of the Data Warehouse database, an application server, and a client or end-user interface. It helps in separating different components for better scalability and maintenance.

The primary purpose of using version control in ETL testing is to track changes in ETL code and configurations. Version control systems allow testers to manage and maintain different versions of ETL scripts, configurations, and other artifacts, facilitating collaboration and ensuring traceability and auditability of changes.

Automation in regression testing for ETL processes plays a crucial role in enhancing speed and efficiency. It helps in quickly validating data consistency across various transformations and ensures that changes do not introduce unexpected errors.

To minimize the impact on source systems, Change Data Capture (CDC) can be used for data extraction. CDC identifies and captures only the changes made to the source data since the last extraction, reducing the load on source systems.

The primary purpose of defect reporting in ETL testing is to identify and document issues or anomalies in the ETL process. This involves detailing the nature of the problem, steps to reproduce it, and its impact on data integrity and processing.

Penetration Testing is a crucial technique in Advanced ETL Security Testing. It involves simulating attacks on the system to identify vulnerabilities and strengthen security measures.