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Understanding the 6 Rs of Cloud Migration

20 January 2022      
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With physical on-premise infrastructure proving to be expensive, requiring CAPEX investment and lacking the agility demanded by a modern business, many organisations are making the move to the cloud. But it’s not as easy as just ‘moving to the cloud’ or enabling a hybrid workforce. Customers are continually consuming data and services in new ways, so it’s critical your business evolves to meet the demands of both today and the future.

Cloud adoption can provide many business benefits. Whether you’re looking to increase agility and speed to market, improve collaboration, unlock the latest technology enhancements or improve your financial posture, it’s essential to plan your migration strategy effectively.

When it comes to cloud migration, maximising value is key. It’s not enough to simply ‘get to the cloud,’ you need to ensure you maximise its value by capitalising on the innovation potential it offers. While brand new applications and solutions make it easy for you to see their value, legacy applications can be much trickier. You’ll need to establish which applications, infrastructure and data architecture need to be modernised, to what extent and how you are going to do it.

That’s where the 6Rs come in.

What are the 6Rs of cloud migration?

Coined by Amazon for AWS and derived from Gartner’s 5Rs model, the 6Rs model is a selection of strategies you can use to perform a cloud migration. While the model might have initially been specific to an Amazon Web Services cloud migration, each strategy can also be used for other public cloud migrations.

When it comes to cloud migration, there are usually a few different reasons why you might decide to make the move. The main reasons tend to be agility, scalability, and trends. These drivers will each have an impact on the migration strategy you choose, so it’s important to understand why you are migrating to the cloud before you consider how you’re going to do it.

When starting your cloud migration journey, it’s crucial that you run a thorough discovery phase to assess what applications are in your environment and decide how you’re going to migrate them, if at all.

Now, let’s dig into what the six strategies are.

1. Rehost

Also known as “lift and shift,” rehosting involves moving applications from an on-premise environment to infrastructure (IaaS) or platforms (PaaS) in the cloud. This strategy is one of the least complicated migration strategies as you would not make significant changes or modifications to the applications.

Many businesses use this strategy to migrate large-scale legacy applications to meet specific or time-sensitive business objectives, for example, to launch a new product quickly. It’s a great method for organisations who need to move at speed or those who need an initial migration before further enhancing their cloud migration with one of the other strategies.

Rehosting can be a great first step in your cloud migration, especially since many apps are easier to re-architect when they’re already in the cloud. The nature of the cloud makes it easy to test your applications in realistic dev environments, enabling you to preview your apps and make sure they take full advantage of the cloud before you go-live.

Creating a clone within the cloud can also provide a competent disaster recovery (DR) plan to facilitate the rapid scaling of an application for service continuity.

While rehosting is relatively easy to implement, it doesn’t come without its downfalls. By effectively copying and pasting the application into the cloud with no modernisations, there is the potential that it won’t be fully equipped to take advantage of the cloud-native environment. Before opting for this strategy, you need to assess your applications to understand which ones can take advantage of the cloud without architectural changes.

2. Replatform

The replatform strategy is like rehosting in that you move applications over to the cloud. However, during the migration stage, you would modernise select components to enable the app to take advantage of the new cloud environment.

There are a few reasons why a business would use this strategy. For businesses with structured legacy systems that cannot be moved over to an IaaS (Infrastructure as a service) cloud platform, replatforming is the solution. In this case, you would mirror the applications through a virtual machine so that legacy IT systems can become compatible with cloud technologies.

Another reason for using this method is to take advantage of agility in the cloud, at speed. This often involves moving away from self-hosted infrastructure and towards managed services, delivering efficiency within platform management costs and overheads whilst also improving the overall security posture with cloud enhancements. By prioritising the applications that only require small optimisations before moving to the cloud, you can quickly replatform them and scale openly on the cloud for increased portability and business agility.

To use this strategy, you will need some programming input and expertise to ensure your migration works as effectively and efficiently as possible. It’s important when replatforming to conduct extensive testing and continuously monitor applications to ensure they have been migrated correctly and achieve performance gains. The ability to enable ongoing testing, tuning and optimisation is made much easier in the cloud too, with DevOps toolkits and ways of working.

It’s important to bear in mind that this strategy can also be expensive to begin with, but the benefits far outweigh the cost implications.

3. Repurchase

This migration strategy is sometimes referred to as “drop and shop” because it involves moving to another product. If you repurchase an application, you effectively decommission the current app and replace it with a cloud-based version. Where possible, this is merely a licensing change and means you can start a new license agreement for the same app, but in the cloud.

Repurchasing is a fast way to access cloud-based applications and can work for a vast selection of apps. It’s worth finding out if your HR, CRM, CMS, or finance applications have cloud equivalents that you can utilise. Sometimes, the cloud versions offer better features or an improved user experience, as well as delivering a more agile cost model.

4. Refactor

Also known as re-architecting, this strategy is useful for businesses that want to make improvements to applications or services. It’s a great option for instances where making improvements to the current environment or improving the reliability of the app with immediate effect is not possible. For example, if you need to improve the availability of an app for an anticipated burst of traffic, you will need to refactor it so it can handle the activity.

Refactoring is usually driven by an organisational need to add features or agility to improve scalability, productivity and collaboration. Businesses will typically need to completely overhaul an application to adapt it to the cloud, breaking it up into independent services before transitioning to microservices and a serverless architecture to unlock greater efficiency gains.

Due to the nature of refactoring, this strategy can be expensive upfront, and you’ll need plenty of expertise to help you do it. However, it can be hugely beneficial when you get it right, with reduced ongoing running costs, reduced management overheads and increased business agility. 

Many applications are refactored in the cloud as part of ongoing cloud evolution in line with a longer-term business strategy. These cloud migration and adoption approaches are interchangeable depending on your business needs and timescales to achieve results.

5. Retain

Put simply, this strategy is where you leave the application as it is or earmark it to revisit later. It’s important during cloud migration that you only move what makes sense for the business at that time. So, if it’s not a priority, leave it for now.

A few reasons why you might decide to retain an application include depreciation value, high migration costs, legacy systems unsupported in the cloud or the value you are currently leveraging from the app on-premise. Some businesses also need to retain certain applications on-premise for compliance reasons, in which case, an application modernisation strategy would make sense.

6. Retire

In your discovery phase, you may have uncovered several applications which are no longer in use. For these applications, you can simply turn them off and retire them, saving you money and lessening the surface area you need to secure.

To find out which applications you can retire, you’ll want to thoroughly assess your apps and think about how much value they add to your business, as well as what the impact would be if you didn’t keep them.

Migrating to the cloud

So, now you know everything about the 6Rs of cloud migration, it’s time to start thinking about your own cloud adoption strategy. Our Cloud Readiness Workshop can help you to review your cloud objectives, discuss technical considerations, and understand the capabilities and skills you need for cloud adoption, ensuring you are prepared and ready for a journey to the cloud. Learn more about the workshop here or get in touch with us to book a free consultation.