4.3.3. Sample Questions - Domain 3: Migration Planning

Question 1:

A company plans to migrate a large on-premises Oracle database to AWS. The database is critical and experiences heavy writes, so downtime must be minimized during the migration. The target database in AWS will be "Amazon Aurora PostgreSQL-compatible". Which AWS service is designed to perform this heterogeneous database migration with continuous data replication and minimal downtime?

A) "AWS Snowball Edge" B) "AWS DataSync" C) "AWS Database Migration Service (DMS)" D) "AWS Application Migration Service (MGN)"

Correct Answer: C

Explanation:

• A) "AWS Snowball Edge": "Snowball Edge" is a physical device for transferring very large amounts of data (PBs) offline into or out of AWS. It's suitable for initial bulk data transfer but does not provide continuous data replication for minimal downtime database migrations.
• B) "AWS DataSync": "DataSync" is an online data transfer service that simplifies, automates, and accelerates moving large amounts of file data between on-premises storage and AWS storage services ("S3", "EFS", "FSx"). It's for file data, not directly for migrating live databases with continuous replication.
• C) "AWS Database Migration Service (DMS)": "AWS DMS" is a fully managed service that supports migrating databases to AWS quickly and securely. It supports both homogeneous (same engine) and heterogeneous (different engines, like Oracle to PostgreSQL) migrations. Crucially, it provides "Change Data Capture (CDC)" to enable continuous data replication, allowing for minimal downtime migrations. This directly addresses the requirements for heterogeneous database migration with continuous data replication and minimal downtime. This aligns with the First Principle of Seamless Database Migration and Zero-Downtime Transition.
• D) "AWS Application Migration Service (MGN)": "AWS MGN" (formerly "CloudEndure Migration") is designed for rehosting (lift-and-shift) entire servers (VMs, physical servers) including their OS, applications, and databases. While it can migrate a server that contains a database, "DMS" is the purpose-built service for migrating the database itself, especially for heterogeneous conversions and continuous replication.

Question 2:

A company needs to migrate thousands of virtual machines from their on-premises "VMware" environment to "Amazon EC2" instances. The migration must have minimal downtime for each server, and the process should be automated and resilient. Which AWS service is the MOST appropriate for this large-scale server rehosting effort?

A) "VM Import/Export" B) "AWS Application Migration Service (AWS MGN)" C) "AWS Server Migration Service (SMS)" D) "AWS DataSync"

Correct Answer: B

Explanation:

• A) "VM Import/Export": "VM Import/Export" is suitable for importing a few virtual machine images to create "EC2 AMIs" or export them. It's a manual, high-downtime process not designed for large-scale, automated migrations with minimal downtime.
• B) "AWS Application Migration Service (AWS MGN)": "AWS MGN" (formerly "CloudEndure Migration") is the recommended service for rehosting (lift-and-shift) physical, virtual, or cloud servers to AWS. It uses continuous, block-level data replication to a lightweight staging area in your AWS account, allowing for highly automated cutovers with minimal downtime (often seconds to minutes). This directly addresses the requirements for large-scale, automated server migration with minimal downtime. This aligns with the First Principle of Automated Server Rehosting and Minimal Downtime Migration.
• C) "AWS Server Migration Service (SMS)" - Deprecated, use MGN: "AWS SMS" was an earlier service for migrating virtual machines from on-premises to "EC2". It has been largely superseded by "AWS MGN", which offers superior capabilities for continuous data replication and automated cutover. The question asks for the MOST appropriate, which is "MGN".
• D) "AWS DataSync": "DataSync" is a service for accelerating online data transfer between on-premises file storage and AWS storage services like "S3" or "EFS". It's for file data, not for migrating entire virtual machines/servers.

Question 3:

An organization has identified a legacy monolithic application that is difficult to scale and maintain. They want to modernize this application on AWS by breaking it down into smaller, independent, and event-driven microservices, leveraging serverless compute. Which application modernization strategy does this approach represent?

A) Rehost B) Replatform C) Refactor/Re-architect D) Repurchase

Correct Answer: C

Explanation:

• A) Rehost (Lift-and-Shift): This involves moving the application as-is to AWS (e.g., VM to "EC2") without significant changes. It doesn't involve breaking down a monolith or adopting serverless.
• B) Replatform (Lift-Tinker-Shift): This involves moving to AWS and making some cloud optimizations, but without changing the core architecture. An example would be moving a self-managed database to "RDS", or containerizing an existing application without changing its internal structure. Breaking down a monolith is more than just tinkering.
• C) Refactor/Re-architect: This strategy involves re-imagining how an application is architected and developed, typically to fully leverage cloud-native capabilities. Breaking a monolith into independent, event-driven microservices and using serverless compute ("Lambda", "DynamoDB") is a classic example of refactoring or re-architecting. This strategy maximizes cloud benefits. This aligns with the First Principle of Cloud-Native Transformation and Agile Modernization.
• D) Repurchase: This involves moving to a different, often "SaaS"-based, product. It means replacing the application entirely, not modernizing its existing codebase.

Question 4:

A company is planning a phased migration of a critical web application to AWS. They need a cutover strategy that ensures near-zero downtime and allows for immediate rollback to the old environment if any issues are detected after switching traffic. Which cutover strategy best meets these requirements?

A) Big Bang Cutover B) Rolling Cutover C) "Blue/Green" Cutover D) Canary Cutover

Correct Answer: C

Explanation:

• A) Big Bang Cutover: This involves switching all traffic at once. It has the highest risk and typically results in significant downtime, making it unsuitable for critical applications needing near-zero downtime.
• B) Rolling Cutover: This strategy updates instances in batches, gradually replacing the old version with the new. While it reduces downtime compared to big bang, rollback can be more complex and slower, and it doesn't offer the instantaneous rollback capability of "Blue/Green".
• C) "Blue/Green" Cutover: This strategy involves running two identical production environments: the "Blue" (old version) and the "Green" (new version). Once the Green environment is fully validated, traffic is switched from Blue to Green. If issues arise, traffic can be instantly reverted back to the Blue environment. This directly addresses the requirements for near-zero downtime and immediate rollback. This aligns with the First Principle of Risk Mitigation and Rapid Recovery in deployments.
• D) Canary Cutover: This strategy gradually rolls out the new version to a small percentage of users first, then gradually to all. While it minimizes the impact of issues to a small subset of users, it doesn't provide an immediate full rollback to the entire old environment in the same way "Blue/Green" does (as "Blue/Green" holds the full old environment ready). "Blue/Green" is typically cited for "immediate rollback of full traffic."

Question 5:

An architect is performing a discovery phase for a large on-premises environment prior to migration. They need to collect detailed inventory data about servers (OS, installed applications, CPU/memory utilization), map dependencies between applications, and identify potential right-sizing opportunities for "EC2 instances" in AWS. Which AWS service is specifically designed to assist with this comprehensive discovery process?

A) "AWS Migration Hub" B) "AWS Application Discovery Service" C) "AWS DataSync" D) "AWS Schema Conversion Tool (SCT)"

Correct Answer: B

Explanation:

• A) "AWS Migration Hub": "Migration Hub" provides a central dashboard to track the progress of migrations from on-premises to AWS. While it uses data from discovery tools, it is not the discovery tool itself.
• B) "AWS Application Discovery Service": "AWS Application Discovery Service" helps you plan your migration by collecting server configuration, performance, and usage data from your on-premises data centers. It identifies interdependencies between applications, provides inventory data, and helps you estimate right-sizing for AWS resources. This directly addresses the need for comprehensive discovery, dependency mapping, and right-sizing analysis. This aligns with the First Principle of Data-Driven Migration Planning and Comprehensive Discovery.
• C) "AWS DataSync": "DataSync" is an online data transfer service for moving file data between on-premises and AWS storage services like "S3" or "EFS". It's for file data, not for discovery and assessment of server configurations.
• D) "AWS Schema Conversion Tool (SCT)": "SCT" is used as part of "AWS DMS" to convert database schemas and application code from one database engine to another (e.g., "Oracle" to "PostgreSQL"). It's specific to database schema conversion, not general server discovery.