Cloud Migration Approach: Rehost, Refactor or Replatform? (2022)

There are several mature, tested approaches to migrating workloads to the cloud. We’ll follow the five approaches in Gartner’s “5 Rs” cloud migration strategy model—rehost (lift and shift), refactor, replatform, rebuild and replace—with a special focus on the first three approaches.

In this post, we’ll review the five cloud migration approaches and explain the lift and shift, refactor and rebuild approaches, with a detailed review of their pros and cons, to help you select the most appropriate approach for each workload. In addition, we’ll show how NetApp Cloud Volumes ONTAP can help with data and storage aspects of your migration.

In this article, you will learn:

    • What Is Cloud Migration?
    • The Lift and Shift Migration Approach and its Pros and Cons
      • Advantages of Lift and Shift Migration
      • Disadvantages of Lift and Shift Migration
    • The Refactoring Migration Approach and its Pros and Cons
      • Advantages of Refactoring
      • Disadvantages of Refactoring
      • The Replatforming Migration Approach and its Pros and Cons
        • Advantages of Replatforming
        • Disadvantages of Replatforming
      • Take Your Cloud Migration Approach with Cloud Volumes ONTAP

What Is Cloud Migration?

Cloud migration is the process of moving some or all your digital operations to your cloud. There are three main types of cloud migration you can perform — on-premises to cloud, cloud to cloud, or cloud to on-premises. When performing any of these three migration types, there are five methods and strategies you can use. The strategies were first defined in the Gartner “5 Rs” model in 2011.These strategies are:

(Video) Cloud Migration Strategies: Rehost, Replatform, Refactor

            • Lift and shift—moving applications to the cloud as-is. This is also sometimes referred to as rehosting.
            • Refactor—modifying applications to better support the cloud environment.
            • Replatform—moving applications to the cloud without major changes, but taking advantage of benefits of the cloud environment.
            • Rebuild—rewrite the application from scratch.
            • Replace—retire the application and replace it with a new cloud-native application.

In the following sections we’ll explain the first three strategies in depth, with their pros and cons.

Also refer to our in-depth article on cloud migration tools that can help you automate and simplify your migration.

1. The Lift and Shift Migration Approach and its Pros and Cons

The “Lift and shift” approach involves dropping the application into the cloud as-is and hoping that it works. Lift and shift is possible for many workloads, and cloud vendors like AWS and Azure are working to make it as easy as possible.

One of the critical steps to ensuring lift and shift actually works is to ensure the application, which until recently operated in the local data center, still has access to the same documents and data once it is in the cloud.

An example is the Microsoft Azure Files service. Azure Files allows cloud VMs to mount file shares that are identical to those in the on-premise environment. This makes lift and shift possible, because you can move workloads from the data center to the cloud, and they still have access to the same shared folders.

(Video) Cloud Migration Strategy - Rehost, Replatform, Repurchase, Refactor, Reachitect, Retain, Retire

Advantages of Lift and Shift Migration

Lift and shift has the following advantages:

            • No code or architecture changes—applications are rehosted to the cloud with no significant application or infrastructure changes, eliminating costly development and testing.
            • Migrate core services easily—you can move critical core services like Active Directory quickly and directly. This presents minimal risk and disruption to business activity.
            • Easier compliance and security management—since applications aren’t changing security and compliance properties also stay largely the same and just need to be mapped to new resources.

Disadvantages of Lift and Shift Migration

Lift and shift has the following disadvantages:

            • Does not take full advantage of the cloud—legacy applications are not scalable and do not allow for distributed workloads like cloud-native applications do.
            • Latency and performance—on-premise applications might suffer from latency or performance issues after migration, because they were not optimized or modified to suit the cloud environment.
            • Increased risk—migrating an application with known problems may result in increased risks after migration.
            • Migration failures—the migration process might fail if the organization doesn't accurately map application requirements to the corresponding cloud configuration.

2. The Refactoring Migration Approach and its Pros and Cons

Refactoring is the process of moving applications to cloud infrastructure, while re-architecting them to better suit the cloud environment. This strategy involves modifying your existing software, or a large chunk of the code base, to take advantage of cloud-based features and the flexibility and elasticity that comes with them.

Refactoring is much more complex than other cloud migration approaches, because it requires application code changes, and needs to be tested carefully to avoid regressions in functionality. You also need to ensure that the application is built for better resource utilization in the cloud, to avoid incurring high costs.

While the refactoring approach is the most time-consuming and resource-intensive, it can provide the highest return on investment once you are running in the cloud.

(Video) Cloud migration, What is the best approach - rehost vs replatform vs refactor | #Shorts

Advantages of Refactoring

The advantages of refactoring are mainly long-term benefits:

            • Long-term cost savings—can reduce costs by matching actual resource requirements with cloud infrastructure. The ability to scale as needed reduces resource consumption and provides long lasting ROI of your refactoring efforts.
            • Adapting to changing requirements—cloud-native and microservices architectures allow applications to rapidly change to adapt to new customer requirements, by adding new features or modifying existing functionality.
            • Increased resilience—by decoupling application components and wiring together managed solutions that provide high availability, the application inherits the durability of this cloud.

Disadvantages of Refactoring

The disadvantages of refactoring are:

            • Vendor lock-in—the more cloud-native your application is, the more cloud features it is likely to consume. This makes applications tightly coupled to the public cloud you are using.
            • Time—refactoring is resource-intensive and much more complex than a lift-and-shift migration, meaning projects take much longer to start showing business value.
            • Skills—refactoring isn't for beginners. It requires advanced coding, automation, and DevOps skills.
            • Getting it wrong—refactoring means changing many aspects of the application, so there is a high risk of errors at the code, configuration, and infrastructure level. Each mistake can cause delays, cost escalations, and possible outages.

3. The Replatforming Migration Approach and its Pros and Cons

A replatform migration is the middle ground between the two strategies we covered above. It’s similar to rehosting applications on the cloud, but it does involve some modification of the application to take advantage of the new cloud infrastructure.

There are some common modifications that are typically performed during replatforming. For example:

            • Changing the way the program interacts with the database to benefit from automation and an elastic database infrastructure.
            • Enabling better scaling and leveraging reserved resources in the cloud environment with minimal code changes.

Advantages of Replatforming

Advantages of replatforming include:

(Video) What's your #cloud #migration #strategy?

            • Cost-efficient—this approach is cost effective and does not require a major development project.
            • Start small and scale as needed—replatforming lets you move some workloads to the cloud, experiment with the cloud environment, learn lessons and then move on to other workloads, without committing to a large migration effort.
            • Cloud-native functionality—re-platforming allows applications to leverage cloud capabilities like auto-scaling, managed storage and data processing services, infrastructure as code (IaC), and more.

Disadvantages of Replatforming

Disadvantages of replatforming include:

            • Work scope can grow—“scope creep” can turn a replatforming project into a full-blown refactoring project. Managing scope and preventing unnecessary changes is essential to mitigate this problem.
            • Aggressive changes—to minimize work, you need to stick to common, well known cloud components. Specialized components often require dramatic changes to the application, and may not be worthwhile unless they provide high business value or use is unavoidable.
            • Automation is required—re-platforming is extremely limited if the resulting workload in the cloud is managed manually. This means you are required to invest in basic automation that provides some level of flexibility when operating the system in the cloud.

Take Your Cloud Migration Approach with Cloud Volumes ONTAP

Migrating to the cloud is a major undertaking. But part of it also involves understanding how your new environment will operate once you get your data to the cloud. Fortunately, NetApp Cloud Volumes ONTAP can help with both.

NetApp Cloud Volumes ONTAP, the leading enterprise-grade storage management solution, delivers secure, proven storage management services on AWS, Azure and Google Cloud. Cloud Volumes ONTAP supports up to a capacity of 368TB, and supports various use cases such as file services, databases, DevOps or any other enterprise workload.

Cloud Migration Approach: Rehost, Refactor or Replatform? (1)

FAQs

What is Rehost in cloud migration? ›

Rehost, commonly referred to as lift and shift, lifts servers or applications from the current hosting environment and shifts them to an infrastructure in the public cloud. Rehosting and lift and shift is a common strategy for organizations just starting their migration journey.

What is the difference between Rehost and Replatform? ›

Replatforming is a happy medium between refactoring and rehosting and applies a series of changes to the application to fit the cloud better without rearchitecting the whole thing versus completely overhauling the application as you would expect from refactoring.

What is refactor in cloud migration? ›

Application Refactoring is the rewriting of one or more components of an application, typically to take advantage of public cloud services. This can also involve refactoring the traditional application into from a legacy 3-tier application design to granular, micro-services based applications.

What are the approaches of cloud migration? ›

These three approaches are lift and shift, application refactoring, and re-platforming –each of which we'll get into, discussing their purpose and migration process.

What does Replatform mean in cloud? ›

Replatforming is a cloud migration strategy that involves modifying a legacy system to work optimally in the cloud without rewriting its core architecture. The replatform strategy goes by other names, like Lift and Reshape, Move and Improve, or the Lift, Tinker, and Shift application migration strategy.

What is Rehost approach? ›

Rehosting (lift and shift) is the process of migrating your on-premises application to the cloud without modifying it. This strategy is used mostly to migrate large-scale applications to satisfy specific business goals, such as launching a product in an accelerated timeline or leaving an on-premises data center.

What is the advantage of using refactor Rearchitect? ›

Legacy applications that are refactored properly will have greater availability, improved scalability, and faster performance. In addition to these advantages, an organization can realize cost benefits after the application has been migrated.

What is refactor in AWS? ›

Refactor Spaces bridges networking across AWS accounts to permit earlier and newer services to communicate while maintaining the independence of separate AWS accounts. Refactor Spaces provides an application that models the Strangler Fig pattern for incremental refactoring.

What are 7rs in cloud migration planning? ›

This data must be evaluated against the seven common migration strategies (7 Rs) for moving applications to the AWS Cloud. These strategies are refactor, replatform, repurchase, rehost, relocate, retain, and retire.

What does it mean to Replatform? ›

What is replatforming? Replatforming involves upgrading an application from its existing platform and adhering to the minimum possible Twelve factors to get it to run on the cloud, while preserving existing functionality.

Is Rehost lift and shift? ›

Rehost (lift and shift)

It is used mostly to migrate large-scale applications to satisfy specific business goals, such as launching a product in an accelerated timeline or exiting an on-premises data center.

What is AWS Replatform? ›

Replatform. This strategy is also known as lift, tinker, and shift or lift and reshape. Using this migration strategy, you move the application to the cloud, and you introduce some level of optimization in order to operate the application efficiently, to reduce costs, or to take advantage of cloud capabilities.

What are two types of cloud migration? ›

The four types of cloud migration are called lift and shift, shift to Software-as-a-Service (SaaS), application refactoring, and replatforming.

What are the 7 types of migration? ›

There are different types of migration such as counter-urbanization, emigration, immigration, internal migration, international migration and rural-urban migration. What are their definitions?

What are the challenges with Replatform? ›

Here's how you can avoid those:
  • Replatforming risk 1: Delays and budget. ...
  • Replatforming risk 2: Lack of prioritization. ...
  • Replatforming risk 3: Indecision. ...
  • Replatforming risk 4: Perfectionism.
6 Jul 2022

What are the 6 R's of migration? ›

Amazon Web Services (AWS) adopted this model and extended it to the 6 R's: Re-host, Re-platform, Re-factor/Re-architect, Re-purchase, Retire and Retain. This post covers the basics for each of these and explains how to decide which AWS migration strategy to choose for your applications.

What is refactoring in Azure? ›

Often referred to as a "repackaging," refactoring requires minimal changes to applications so that they can connect to Azure platform as a service (PaaS) and use cloud offerings. For example, you could migrate existing applications to Azure App Service or Azure Kubernetes Service (AKS).

What is a software Rehost? ›

In simple terms, legacy software rehosting, also known as lift-and-shift, is a process of moving a legacy software application to a different platform, avoiding significant changes. This approach solves the issue of expensive maintenance by moving the system from its legacy hardware to modern hosting solutions.

How many steps are there in migration? ›

There are four major forms of migration: invasion, conquest, colonization and emigration/immigration.

What are the 6 R's in AWS? ›

The 6 Rs model includes: Rehost, Replatform, Repurchase, Refactor, Retire and Retain.

What is Rearchitect in cloud? ›

Re-architect, Re-host, Re-platform

This means breaking an application down and rebuilding it in a service-oriented, scalable design. Doing this lets you get the most benefits from a cloud platform, allowing you to easily add capacity and manage the cost of the service.

Which three methods are examples of application migration techniques? ›

6 Application Migration Strategies: “The 6 R's”
  • Replatforming — I sometimes call this “lift-tinker-and-shift.” ...
  • Repurchasing — Moving to a different product. ...
  • Refactoring / Re-architecting — Re-imagining how the application is architected and developed, typically using cloud-native features. ...
  • Retire — Get rid of.
1 Nov 2016

How can we make migration effective? ›

8 Key Steps to a Successful Migration
  1. Discovery & Analysis. ...
  2. Get all Stakeholders Involved. ...
  3. Create a Cloud Readiness Plan. ...
  4. Manage Deadlines. ...
  5. Communicate Roles & Expectations. ...
  6. Pay Attention to Security Risks. ...
  7. Create a Pilot Project. ...
  8. Testing and Validating.
16 Oct 2018

What are the 3 R's of migration strategy? ›

Application Migration Strategies - The 3 R's
  • Rehosting. ...
  • Replatforming. ...
  • Refactoring / Re-architecting (and a little bit of repurchasing)
12 Apr 2022

What is AWS migration? ›

AWS Application Migration Service simplifies and expedites your migration to the cloud. It allows you to quickly realize the benefits of migrating applications to the cloud without changes and with minimal downtime.

What is 6R analysis? ›

6R framework proposes a separation of your apps into six strategies: Re-host, Re-platform, Re-factor/Re-architect, Re-purchase, Retire, and Retain. Based on the requirements, we create a clear migration plan for each application in your portfolio.

What are four four important factors of planning cloud deployment? ›

Organizations must take into account four important factors: security, performance, integration and legal requirements.

What are 3 key factors in defining cost on cloud storage? ›

Capacity, transactions, Networking are the three main key factors in defining cost on cloud storage.

What are the four types of cloud networking? ›

There are four main types of cloud computing: private clouds, public clouds, hybrid clouds, and multiclouds.

What does it mean to Replatform a website? ›

Replatforming a website is the process of moving your current from its existing CMS (content management system) to a new CMS. It's not necessarily about a re-design, it's more about positioning your website, app and entire digital presence to succeed in the next generation of the internet.

Is Replatform a word? ›

Refers to the process by which an online brand changes from one platform to another.

What is lift and shift cloud migration? ›

Lift and Shift Meaning. The lift and shift migration approach is about migrating your application and associated data to the cloud with minimal or no changes. Applications are effectively “lifted” from the existing environments and “shifted” as-is to a new hosting premises; i.e. in the cloud.

What is a benefit of using a lift and shift approach? ›

The lift-and-shift approach opens paths to IT modernization by moving to an open and more extensible architecture in the cloud. Companies consider lift and shift for solid business reasons, including reduced costs and improved performance and resiliency.

Which tool is used for cloud migration? ›

Carbonite Migrate is the company's data and application migration tool for cloud environments.

What does a lift and shift mean? ›

What is lift and shift? “Lift and shift,” also known as “rehosting,” is the process of migrating an exact copy of an application or workload (and its data store and OS) from IT one environment to another—usually from on-premises to public or private cloud.

What is the difference between Rehost and relocate? ›

For organisations whose on-prem IT runs on VMware, relocation is basically rehosting, but specifically designed to enable you to create a virtual copy of your datacenter in the cloud.

What are the three phases of AWS cloud migration? ›

AWS approaches large-scale migrations in three phases: assess, mobilize, and migrate. Each phase builds on the previous one. This AWS Prescriptive Guidance strategy covers the assess phase and the mobilize phase. These phases set the foundation for accelerated migration at scale during the migrations phase.

How do I migrate to the cloud? ›

The cloud migration checklist includes:
  1. Establish the migration-architect role.
  2. Choose your level of cloud integration.
  3. Choose a single cloud or go multi-cloud.
  4. Establish cloud KPIs.
  5. Establish performance baselines.
  6. Prioritize migration components.
  7. Perform any necessary refactoring.
  8. Create a data-migration plan.
23 Feb 2021

What are the types of migration? ›

internal migration: moving within a state, country, or continent. external migration: moving to a different state, country, or continent. emigration: leaving one country to move to another. immigration: moving into a new country.

What is cloud migration with example? ›

Furthermore, you can complete a cloud migration by switching from one cloud computing provider to another. This migration approach is called a cloud-to-cloud migration. For example, you can switch from Google Cloud Platform (GCP) to either Microsoft Azure Cloud Services or Amazon Web Services (AWS), and vice versa.

Why is cloud migration important? ›

A cloud migration allows your business to expand and grow painlessly while working within the existing infrastructure. This means applications and data can grow without impacting your business performance or customer experience.

How is cloud migration done in process? ›

Step-by-Step Cloud Migration Process

Evaluate your migration costs and needs. Assess the environment and applications. Choose cloud environment (single or multi-cloud) Determine deployment model (IaaS, PaaS & SaaS)

What is public cloud Mcq? ›

Answer: B. Explanation: Cloud computing is a computing technique in which applications are accessed by common internet protocols and networking standards.

What are the 5 effects of migration? ›

The consequences of migration for developing countries include the following aspects: 1) adaptation of labor markets to demands of the economy, 2) degree and type of concentration of migrant populations in the receiving country, 3) differences that arise between formal and informal and urban and rural sectors of the ...

What are the 10 reasons for migration? ›

They include:
  • lack of services.
  • lack of safety.
  • high crime.
  • crop failure.
  • drought.
  • flooding.
  • poverty.
  • war.

What are the factors of migration? ›

The non-availability of alternative sources of income in rural area is also important factor for migration. The Pull Factors are factors which attract the migrants to an area. Opportunities for better employment, higher wages, facilities, better working conditions and attractive amenities are pull factors of an area.

What does it mean to Replatform? ›

What is replatforming? Replatforming involves upgrading an application from its existing platform and adhering to the minimum possible Twelve factors to get it to run on the cloud, while preserving existing functionality.

What are the 6 R's of migration? ›

Amazon Web Services (AWS) adopted this model and extended it to the 6 R's: Re-host, Re-platform, Re-factor/Re-architect, Re-purchase, Retire and Retain. This post covers the basics for each of these and explains how to decide which AWS migration strategy to choose for your applications.

What is refactoring in AWS? ›

The refactor environment provides unified networking across accounts by orchestrating AWS Transit Gateway, AWS Resource Access Manager, and virtual private clouds (VPCs). The refactor environment contains your existing application and new microservices.

What are 7rs in cloud migration planning? ›

This data must be evaluated against the seven common migration strategies (7 Rs) for moving applications to the AWS Cloud. These strategies are refactor, replatform, repurchase, rehost, relocate, retain, and retire.

What are the challenges with Replatform? ›

Here's how you can avoid those:
  • Replatforming risk 1: Delays and budget. ...
  • Replatforming risk 2: Lack of prioritization. ...
  • Replatforming risk 3: Indecision. ...
  • Replatforming risk 4: Perfectionism.
6 Jul 2022

What is refactoring in Azure? ›

Often referred to as a "repackaging," refactoring requires minimal changes to applications so that they can connect to Azure platform as a service (PaaS) and use cloud offerings. For example, you could migrate existing applications to Azure App Service or Azure Kubernetes Service (AKS).

How many types of cloud migration are there? ›

The four types of cloud migration are called lift and shift, shift to Software-as-a-Service (SaaS), application refactoring, and replatforming.

What is 6r Principle? ›

6Rs: Rethink, Refuse, Reduce, Reuse, Recycle, Repair

These are all useful terms to explore reducing the impact of technology on people and the environment.

Which tool is used for cloud migration? ›

Carbonite Migrate is the company's data and application migration tool for cloud environments.

What are the 6 R's in AWS? ›

The 6 Rs model includes: Rehost, Replatform, Repurchase, Refactor, Retire and Retain.

What is AWS Replatform? ›

Replatform. This strategy is also known as lift, tinker, and shift or lift and reshape. Using this migration strategy, you move the application to the cloud, and you introduce some level of optimization in order to operate the application efficiently, to reduce costs, or to take advantage of cloud capabilities.

What are the 3 R's of migration strategy? ›

Application Migration Strategies - The 3 R's
  • Rehosting. ...
  • Replatforming. ...
  • Refactoring / Re-architecting (and a little bit of repurchasing)
12 Apr 2022

Is Rehost lift and shift? ›

Rehost (lift and shift)

It is used mostly to migrate large-scale applications to satisfy specific business goals, such as launching a product in an accelerated timeline or exiting an on-premises data center.

What are four four important factors of planning cloud deployment? ›

Organizations must take into account four important factors: security, performance, integration and legal requirements.

What are 3 key factors in defining cost on cloud storage? ›

Capacity, transactions, Networking are the three main key factors in defining cost on cloud storage.

What are the four types of cloud networking? ›

There are four main types of cloud computing: private clouds, public clouds, hybrid clouds, and multiclouds.

Videos

1. Rehost or Rearchitect - Understanding the Why and How of Very Different Paths to Cloud Success
(Amazon Web Services)
2. Migration Strategies For Beginners - Rehost, Replatform, Repurchase, refactor
(Cloud Academy - All in One)
3. 5 Options for Moving to the Cloud & Why You Should Rehost
(LiquidWeb)
4. 94 - How to develop a cloud migration strategy?
(OTechTalks)
5. Cloud Migration Strategy | 6Rs | Cloud Computing
(Learning Knack)
6. App Modernization: Rehost, Refactor, Rearchitect, or Rebuild?
(Oracle Developers)

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