When Should You Use AWS MGN? Use Cases & Limitations.

What is MGN.

AWS MGN, short for AWS Application Migration Service, is a fully managed cloud migration service provided by Amazon Web Services that enables users to lift and shift physical, virtual, or cloud-based servers into the AWS Cloud with minimal downtime and without requiring any manual conversions or code changes.

It is designed to simplify and accelerate the migration process by automating the replication of entire servers operating systems, applications, and data into the AWS environment. This eliminates the need for complex re-architecting or extensive planning commonly associated with cloud migrations.

AWS MGN continuously replicates source servers to a low-cost staging area within the AWS account, ensuring up-to-date copies of workloads. Once the servers are replicated, users can launch them as Amazon EC2 instances, test their functionality, and cut over to AWS production systems with minimal disruption.

The service supports Windows and Linux operating systems and is capable of migrating workloads from on-premises data centers, VMware, Hyper-V, or even from other cloud providers. AWS MGN uses block-level replication to ensure high fidelity and consistency of data, which makes it ideal for critical applications that require accuracy during migration.

It offers built-in testing and cutover orchestration, allowing users to verify their applications in AWS before fully switching over, thereby reducing the risk of errors during go-live events. The interface is integrated into the AWS Management Console, making it accessible and user-friendly even for teams with limited AWS experience.

One of the core strengths of AWS MGN is its ability to scale large migration projects by allowing organizations to migrate dozens, hundreds, or even thousands of servers in a repeatable and streamlined manner.

Organizations undergoing data center evacuations, cloud consolidation, or digital transformation often turn to MGN as their preferred solution for rehosting workloads quickly and reliably. Since the service replicates entire servers, it supports legacy applications and systems that cannot be easily containerized or rearchitected, making it a practical option for maintaining business continuity during cloud adoption.

In terms of security, AWS MGN leverages AWS’s built-in capabilities, such as IAM (Identity and Access Management), encryption in transit and at rest, and VPC configurations, ensuring data protection throughout the migration lifecycle.

After the migration, organizations can optimize their EC2 instances, apply modernization strategies, or integrate their systems with other AWS services. Despite its many advantages, AWS MGN is best suited for rehosting scenarios and is not intended for migrations requiring application refactoring or real-time data synchronization. For these, other tools like AWS DMS (Database Migration Service) or App2Container may be more appropriate.

AWS MGN is a robust, cost-effective, and time-saving migration tool that empowers organizations to move workloads to AWS seamlessly. It supports a wide range of operating systems and infrastructure types, offering a consistent, repeatable migration process with minimal disruption to business operations. AWS MGN helps reduce operational risk by enabling test launches, automates critical migration steps, and integrates with AWS best practices. As cloud adoption continues to grow, AWS MGN remains a pivotal service for enterprises looking to transition efficiently to AWS without rewriting their applications or disrupting critical services.

When Should You Use AWS MGN?

Primary Use Cases

1. Lift-and-Shift Migrations (Rehosting)
   • Goal: Move workloads with minimal/no refactoring.
   • Use Case: Quickly migrate servers and applications to AWS to reduce on-premises costs or to meet a cloud adoption deadline.
2. Data Center Evacuations
   • Goal: Shut down an entire data center by moving workloads to the cloud.
   • Use Case: A business wants to eliminate on-prem infrastructure and migrate everything to AWS.
3. Cloud-to-Cloud Migrations
   • Goal: Move workloads from other cloud providers (e.g., Azure, GCP) to AWS.
   • Use Case: A company is consolidating its workloads on AWS.
4. Business Continuity & Disaster Recovery Setup
   • Goal: Use AWS as a backup environment.
   • Use Case: MGN is used to replicate on-prem servers to AWS as a fallback DR site.
5. Legacy App Migration
   • Goal: Migrate apps that can’t be easily containerized or rewritten.
   • Use Case: Legacy Windows/Linux applications that need to stay intact in the cloud.
6. Test Environments in the Cloud
   • Goal: Use AWS to create temporary testing environments.
   • Use Case: Migrate production clones to AWS for testing patches or updates without impacting live systems.

When Not to Use AWS MGN

Limitations & Better Alternatives

1. You Need Refactoring or Replatforming
   • Reason: AWS MGN doesn’t support application transformation.
   • Use AWS Application Migration Hub, Elastic Beanstalk, or App2Container for modernizing workloads.
2. Container-Based Workloads
   • Reason: MGN is designed for VM and physical servers, not containers.
   • Use ECS, EKS, or App2Container.
3. Migrate Only Data, Not Entire Servers
   • Reason: MGN migrates entire systems, not just files or databases.
   • Use AWS DataSync, Snowball, or Database Migration Service (DMS).
4. Real-Time or Continuous Synchronization Use Cases
   • Reason: MGN is optimized for one-time migrations, not continuous replication.
   • Use AWS DataSync or a third-party tool for ongoing sync.
5. Unsupported Operating Systems
   • Reason: MGN supports many OS types, but not all.
   • Check compatibility; unsupported systems may require manual migration or third-party tools.

How It Works (Brief Overview)

1. Install MGN Agent on source servers (on-prem, cloud, or virtual).
2. Continuous replication to a staging area in AWS.
3. Launch test instances to validate.
4. Cut over to AWS with minimal downtime.
5. Decommission source environment (optional).

Summary Table

Conclusion.

AWS MGN (Application Migration Service) is a powerful, fully managed tool that simplifies and accelerates the process of migrating servers to the AWS Cloud. It enables organizations to perform seamless lift-and-shift migrations with minimal downtime, no need for code changes, and high reliability.

Ideal for migrating legacy systems, large-scale environments, or workloads that must remain intact, MGN provides an efficient path to cloud adoption while reducing manual effort and risk.

Although it’s not designed for application modernization or container migrations, it plays a critical role in cloud migration strategies where speed, simplicity, and system integrity are priorities. By using AWS MGN, businesses can move to the cloud faster, reduce on-premises costs, and lay the foundation for future cloud-native innovation.