Crack Your AWS Database Migration Service Interview: Top 10 Questions and Solutions

Here are the top 10 AWS DMS (Database Migration Service) interview questions along with their answers:

1. What is AWS DMS, and what are its key features?
   Answer: AWS DMS is a managed service that helps migrate databases to AWS quickly and securely. Its key features include continuous data replication, schema conversion, data validation, and support for a wide range of database sources and targets.

2. What are the different database migration methods supported by AWS DMS? Answer: AWS DMS supports several migration methods, including homogeneous migrations (e.g., Oracle to Oracle) and heterogeneous migrations (e.g., Oracle to Amazon Aurora). It also supports full database migrations and ongoing replication.

3. How does AWS DMS handle schema and data transformations during migration?
   Answer: AWS DMS provides a schema conversion tool that helps convert database schema objects, such as tables and indexes, to the target database format. It also supports data transformations through custom table and column mappings.

4. Can AWS DMS perform a database migration with minimal downtime?
   Answer: Yes, AWS DMS provides a feature called "Change Data Capture" (CDC), which allows continuous replication of changes from the source database to the target database. This minimizes downtime during the migration process.

5. What are the prerequisites for using AWS DMS?
   Answer: To use AWS DMS, you need a source and a target database, an AWS account, and appropriate database credentials. The source and target databases should be accessible from the AWS DMS service.

6. How does AWS DMS ensure data integrity during migration?
   Answer: AWS DMS ensures data integrity by using validation checks during and after the migration process. It provides options for table-level validation and comparison of source and target data to identify any inconsistencies.

7. What are the monitoring and troubleshooting capabilities of AWS DMS?
   Answer: AWS DMS offers a comprehensive set of monitoring features, including CloudWatch metrics, event notifications, and the ability to view and analyze replication tasks. It also provides detailed logs for troubleshooting purposes.

8. Can AWS DMS migrate data from on-premises databases to the cloud?
   Answer: Yes, AWS DMS supports migrating data from on-premises databases to the cloud. You can deploy the AWS DMS replication instance within your on-premises environment to facilitate the migration.

9. How does AWS DMS handle data replication in heterogeneous database migrations?
   Answer: AWS DMS uses a combination of database-specific change data capture techniques, such as reading transaction logs, triggers, or database-specific APIs, to capture changes from the source database and replicate them to the target.

10. What are the limitations of AWS DMS?
    Answer: Some limitations of AWS DMS include a limited number of concurrent replications, certain database-specific features not supported during migration, and potential network and latency issues in cross-region migrations.

Remember to tailor your answers based on your specific experience and expertise in AWS DMS.