Cloud Migration Strategies: The 7 Rs Explained

This framework is a set of approaches designed to help organisations plan and execute their migration to the cloud effectively. Originally introduced by Gartner in the early days of cloud computing as the "5 Rs," the model has since evolved to include two additional strategies, reflecting the growing complexity and maturity of modern cloud and infrastructure services. 

By assessing your IT portfolio against these seven strategies, you can minimise risk, control costs, and ensure your technology aligns perfectly with your business objectives. 

What are the 7 Rs of cloud migration strategy? 

The "7 Rs" represent the key strategies businesses use to transition workloads to the cloud. Each approach addresses different types of workloads, organisational needs, and objectives. Here's a closer look at each method:

1. Rehost (Lift and Shift)

Rehosting is the simplest and most common migration method. It involves moving your existing applications and data from on-premises servers to cloud Infrastructure-as-a-Service (IaaS) without making any significant changes to the underlying code.  

Many businesses use this strategy when they need to migrate quickly (e.g., to exit a data centre) or lack the internal resources to reconfigure their applications. Rehosting often acts as a first step, allowing organisations to modernise applications once they are already stable in the cloud environment. 

• Advantages: Offers the quickest possible cloud migration, makes the transition procedure less complicated, and reduces initial capital expenses by steering clear of significant redesigns. 

• Limitations: Doesn't fully utilise cloud-native capabilities (like auto-scaling) that could save costs and increase performance. It can also carry existing inefficiencies and technical debt into the new cloud environment.

2. Relocate(Hypervisor-Level Lift and Shift) 

Relocation is similar to Rehosting but operates at the hypervisor level. This strategy involves moving entire virtual machines (VMs) to cloud infrastructure without making any changes to the applications or the operating systems. Relocation is particularly beneficial for businesses using VMware or similar environments (such as moving to Azure VMware Solution) looking for a rapid transition without disrupting active services. 

• Advantages: No application changes are required, saving time and resources. Organisations can maintain their existing tooling and configurations, making the process highly familiar for IT teams and minimising operational disruption. 

• Limitations: Applications moved without modification may not fully utilise cloud-native cost efficiencies. Workloads optimised for on-premises infrastructure may not perform as efficiently in the cloud, and the approach restricts elastic scaling capabilities. 

3. Replatform(Lift and Reshape) 

Replatforming is about making targeted, minor adjustments to your applications while migrating them to the cloud. These tweaks are usually made to take advantage of specific cloud capabilities, such as managed services, without restructuring the entire application. For instance, a business might migrate an application as-is, but swap out its self-managed legacy database for a fully managed cloud-native database service (like Azure SQL) to reduce maintenance overhead. 

• Advantages: Increases productivity by adapting apps to use cloud-native capabilities like managed services. It lowers operating costs compared to simple Rehosting and is significantly less risky and time-consuming than a complete re-architecture. 
• Limitations: Despite the advancements, not all cloud-native features are completely utilised. Some components of the application will still require modification and testing to integrate smoothly into the new environment.

4. Refactor (Re-architect)

Refactoring involves significant modifications or completely rebuilding applications to be truly "cloud native." This strategy focuses on leveraging advanced cloud features such as microservices architecture, serverless computing, or containerisation to maximise performance. While it requires the highest level of upfront investment and technical expertise, Refactoring delivers exceptional scalability, agility, and long-term ROI. 

• Advantages: Delivers full optimisation, enhancing performance, scalability, and resilience. It enables the adoption of contemporary development techniques and, despite high initial costs, results in the lowest long-term operating expenses. 
• Limitations: Requires a large time, resource, and skill commitment. The intricate restructuring can lead to challenges during the transition and may cause business disruption while the migration is underway.

5. Repurchase (Drop and Shop)

Repurchasing refers to abandoning an existing legacy application and replacing it with a new, cloud-based solution. Typically, businesses opt for Software-as-a-Service (SaaS) platforms that better meet their modern needs. For example, migrating from a highly customised, on-premises CRM or HR system to a cloud platform like Salesforce or Workday. This strategy is highly effective when the existing application no longer aligns with business needs or when upgrading the legacy system is cost prohibitive. 

• Advantages: Streamlines IT portfolios by lowering the quantity of custom apps that require internal management. It gives users immediate access to the newest features and shifts the burden of maintenance and security updates to the SaaS provider. 
• Limitations: Introduces ongoing subscription costs (OpEx). It may also present data migration and integration difficulties, and there is a chance the new off-the-shelf product won't have every bespoke feature of the legacy system.

6. Retire (“Get Rid of”)

During the discovery phase of a cloud migration, companies often identify workloads, environments, or applications that are no longer adding value. Retiring these antiquated resources not only reduces costs but simplifies the entire migration effort. A thorough review of your IT portfolio often reveals that up to 10-20% of an enterprise's applications are no longer necessary and can be safely decommissioned. 

• Advantages: Instantly reduces costs by removing the need to maintain, license, and power antiquated systems. It simplifies the IT environment and enables teams to focus their budget and effort on systems that offer genuine business value. 

• Limitations: Determining which systems should be decommissioned—and reaching a consensus across different departments—can be politically challenging. Strict alignment with business units is necessary to guarantee no crucial background activities are interrupted. 

7. Retain(“Revisit”) 

Sometimes, the best strategic decision is not to migrate a workload at all. If certain data or applications still offer high value while operating efficiently in their current environment, retaining them on-premises until a later migration phase might be the wisest choice. For example, legacy workloads with strict data sovereignty compliance restrictions, or applications that have recently received heavy capital investment, may be retained in a hybrid cloud model. 

• Advantages: Guarantees that strict legal, regulatory, and compliance requirements are properly followed. It maintains the stability of highly sensitive applications and prevents needless migration expenses for systems that are not yet cloud ready. 

• Limitations: Retained apps miss out on the scalability and resilience of cloud services. It also preserves the complexity of managing a hybrid environment, requiring IT teams to support both on-premises infrastructure and the new cloud environment. 

When should you use each migration model? 

Understanding when to apply each strategy is vital to making informed, cost-effective decisions. Here’s a simplified table to help you choose the right model based on workload, urgency, and organisational goals: 

Strategy	Best Used When...
Rehost	Quick cloud adoption (e.g., data centre exit) is required, and minimal effort or resources are available for code changes.
Relocate	Virtual machines (like VMware) are being migrated directly without the underlying applications being refactored or updated.
Replatform	Minor optimisations are needed to take advantage of managed cloud features (like databases) during the migration.
Refactor	Core applications are being fully modernised for maximum long-term scalability, agility, and cost-efficiency.
Repurchase	Current legacy applications are deemed no longer fit for business requirements, and standard SaaS alternatives are required.
Retire	Legacy applications, redundant systems, or workloads are identified as no longer holding any business value.
Retain	Critical workloads are bound by strict compliance, or are deemed best suited for on-premises infrastructure until future migration is viable.

How OneAdvanced can help 

Navigating the complexities of the 7 Rs requires deep technical expertise and strategic foresight. OneAdvanced's relationship with Microsoft goes back over 30 years, during which our Azure experts have helped numerous organisations leverage the full benefits of the cloud. 

Whether you are looking to Rehost your infrastructure or Refactor your core applications, we advise, assist, secure, and operate—wherever you may be on your cloud journey. 

Get in touch with our IT Services team today to see how we can help you build a seamless, secure, and cost-effective cloud migration strategy. 

Frequently Asked Questions (FAQs) 

What is the most common cloud migration strategy?  

Rehosting (Lift and Shift) is generally the most common starting point for businesses. It allows organisations to move to the cloud quickly and close down on-premises data centres, giving them the breathing room to Replatform or Refactor applications at a later date. 

How do I choose the right cloud migration strategy?  

Choosing the right strategy requires a comprehensive audit of your current IT portfolio. You must evaluate each application based on its business value, technical complexity, compliance requirements, and the total cost of ownership (TCO) of moving it versus keeping it on-premises. 

Can I use multiple migration strategies at once?  

Yes. In fact, a successful enterprise cloud migration almost always uses a combination of the 7 Rs. A business might Rehost their standard web servers, Refactor their customer-facing mobile app, Repurchase their HR software, and Retire outdated internal tools all within the same migration project.