> For the complete documentation index, see [llms.txt](https://ghoulsec.gitbook.io/ghoulsec-vault/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://ghoulsec.gitbook.io/ghoulsec-vault/exam-prep-notes/aws-cloud-practitioner/aws-migration-and-innovation/migration-statergies.md).

# Migration Statergies

AWS Follows 6 R's of Migration steps , The **6 R's** of AWS Migration Strategies provide a structured approach to migrate applications to the cloud. Each strategy addresses a specific use case or scenario based on business and technical needs.

<details>

<summary>Rehosting (Lift-and-Shift)</summary>

* **Description**: Moving applications to the cloud with minimal or no modifications.
* **Key Features**:
  * Typically involves migrating workloads as-is.
  * Useful when rapid migration is needed or when legacy applications are not cloud-optimized.
* **Use Cases**:
  * Applications with no immediate need for redesign.
  * Scenarios requiring quick migration to meet deadlines.
* **Tools**: AWS Migration Hub, AWS Application Migration Service (MGN).

</details>

<details>

<summary>Replatforming (Lift, Tinker, and Shift)</summary>

* **Description**: Making minimal changes to applications during migration to optimize performance or cost in the cloud.
* **Key Features**:
  * Minor adjustments like upgrading to a managed database service (e.g., moving from MySQL on-premises to Amazon RDS).
  * Balances speed of migration with some level of optimization.
* **Use Cases**:
  * Applications needing slight improvements without a full rearchitecture.
  * Reducing management overhead (e.g., moving to managed services).
* **Examples**: Replacing self-hosted databases with AWS-managed solutions.

</details>

<details>

<summary>Retire</summary>

* **Description**: Decommissioning or phasing out unused or redundant applications.
* **Key Features**:
  * Reduces costs by eliminating unnecessary workloads.
  * Identifies applications that no longer serve business objectives.
* **Use Cases**:
  * Legacy systems with no future requirements.
  * Consolidation of functions into fewer systems.
* **Tools**: Cost analysis and dependency mapping tools.

</details>

<details>

<summary>Retain (Keep as-is)</summary>

* **Description**: Keeping certain applications in their current environment (on-premises or legacy systems).
* **Key Features**:
  * Applies to systems that cannot or should not be migrated (e.g., due to latency, compliance, or dependency reasons).
  * These applications may still integrate with cloud workloads.
* **Use Cases**:
  * Applications reliant on specialized hardware.
  * Systems needing long-term on-premises presence due to compliance or latency.
* **Examples**: Retaining ERP systems or industrial control systems.

</details>

<details>

<summary>Repurchasing</summary>

* **Description**: Replacing existing applications with new cloud-native solutions, often using SaaS.
* **Key Features**:
  * Typically involves abandoning legacy applications and adopting modern equivalents.
  * Shifts from license-based software to subscription-based SaaS.
* **Use Cases**:
  * Outdated or costly legacy systems.
  * Adopting cloud-native solutions for improved functionality or cost efficiency.
* **Examples**: Moving from a self-hosted CRM to Salesforce.

</details>

<details>

<summary>Refactoring (Re-architecting)</summary>

* **Description**: Reimagining and re-engineering applications to leverage cloud-native features.
* **Key Features**:
  * Significant changes to application code and architecture.
  * Unlocks advanced cloud benefits like serverless computing, microservices, and scalability.
* **Use Cases**:
  * Applications needing enhanced scalability, agility, or performance.
  * Legacy systems hindering business innovation.
* **Examples**: Breaking monolithic applications into microservices using AWS Lambda or Amazon ECS.

</details>

#### Strategy Selection Criteria

1. **Business Goals**: How critical is speed, cost, or scalability?
2. **Technical Feasibility**: Can the application be modernized or must it remain as-is?
3. **Time and Resource Constraints**: How much time and resources are available for migration?
4. **Compliance Requirements**: Are there regulatory constraints on where data or applications can reside?

The **6 R's** provide a flexible framework to tailor migration strategies to meet diverse business and technical needs.