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Lift and Shift Migration Vs Rearchitecting: Which is the Better Migration Strategy?

When considering a move to the cloud, one of the most important decisions to make involves how you will transition your resources from on-premises infrastructure. This is not a simple matter, as there is no single “right answer” to cloud migration. Instead, you must closely examine the potential benefits and drawbacks of various strategies. Only through proper research and deliberation will you find and choose the right migration option to facilitate optimal cloud computing adoption for your organisation.

In this blog, we’re taking a thorough look at two of the most well-known cloud migration methods: lift and shift versus rearchitecting. These two examples of migration strategy have ardent proponents and strong skeptics, and differ considerably in their processes and complexity.

Lift and Shift to the Cloud: The Fundamentals

Let’s begin with lift and shift, which is also sometimes called rehosting.

As the name suggests, in a lift and shift migration, an application and its data (sometimes referred to jointly as a workload), are moved directly from an on-premises server to an infrastructure-as-a-service (IaaS) platform of a public cloud provider like Microsoft Azure or Amazon Web Services (AWS). Very few — if any — architectural changes are made to the app. Any refactoring of the underlying code is similarly minimal.

The reasoning expressed by lift-and-shift proponents is that migrating the application with little or no changes provides access to the inherent benefits of cloud deployment in the cheapest and fastest way.  As such, lift and shift is the most common approach for migrating on-premises resources to cloud infrastructure. Tools offered by cloud platform providers to ease the migration process in this way include Azure Migrate and AWS’ Application Migration Service. These are advertised as one-stop solutions to migrate from any environment to the cloud. In the most technical sense, those characterisations are correct; whether this means they are the ideal method of migrating applications is another matter entirely.

Note, if you’re curious about how this migration approach would play out in the integration sphere, we wrote a blog looking at one of these tools in depth: The BizTalk Migrator/Azure Integration Migrator. It is well worth a read if considering lift and shift migration as a strategy for bringing integration systems into cloud environments.

Azure Migrate - Hub for Datacentre Migration

Benefits of Lift and Shift

  • For those seeking a quick path to the cloud, this route is the fastest in most cases.
  • You can use your knowledge of managing existing on-premises infrastructure while upskilling in cloud adoption and continuing to work every day. This is often optimal for SMBs, or other organisations that are new to the cloud and only just embarking on their journey to digital transformation.
  • It is a relatively inexpensive option and provides immediate cost benefits.

Drawbacks of Lift and Shift

  • “Fastest” does not necessarily mean “best.”
  • Despite near-term savings, ongoing operational costs can eventually become unduly expensive, because you’re not truly leveraging cloud efficiencies.
  • Due to the lack of rearchitecting and native cloud features, applications will run without optimisation, thus failing to reach their full potential.

When to Use Lift and Shift to the Cloud?

Every case is different, but many organisations that opt for this type of migration do so when they rapidly want to lower the cost of on-premises infrastructure. Alternatively, lift and shift might become the strategy of choice if the lease on a company’s data centre is near expiration and fast-paced migration is required, or if the end of support for older on-premises products is at hand.

In such cases, as well as for organisations very new to cloud deployments, lift and shift may serve as a viable short-term solution. But the disadvantages noted above — perhaps above all, the strategy’s inability to allow a truly cloud-native approach — mean that there are significant limitations to its long-term value.

Application Rearchitecting

Now, let’s take a look at the rearchitecting method of cloud migration, also known as refactoring.

What is Rearchitecting?

Rearchitecting involves revamping old legacy applications into modern architecture. This may involve modifying the application, adding new features, discarding unwanted functions and potentially rewriting the majority of the application code.

Although this is not the most common approach when compared to lift and shift, many mid-scale and large-scale companies rearchitect their core products and services before migrating to the cloud. This means the apps, once migrated, are cloud-native, and these organisations can make the most of the cloud’s scalability and elasticity to optimize application performance. As businesses’ needs change from time to time, it’s easier to modify the functionality of cloud-native apps to meet those needs.

Benefits of Rearchitecting

  • Create fully optimised and modern applications built to take advantage flexibility of cloud deployments.
  • Adjust cloud-native apps to meet changing business requirements.
  • Save money in the long term.

Drawbacks of Rearchitecting

  • Longer journey to the cloud because applications need to be significantly modified or completely rewritten before migration.
  • Higher upfront costs (due to the development work required in app modernisation).
  • Maintaining the high performance of cloud-native apps requires a skilled dev team (or experienced partners).

When to Rearchitect before Migration?

For larger businesses with more complex software, rearchitecting apps before migration can often make the most sense in the long term. Your legacy software upholds day-to-day operations, meaning there is no downtime while your software gets the facelift it needs for the cloud. If you have the money and time to invest in the rearchitecting strategy, its long-term rewards can be great.

Rearchitecting Leading to Successful Cloud Migration: A case study

Netflix is one of the best examples of rearchitecting serving as the foundation for long-term success in the cloud. It took almost seven years for Netflix to migrate to the cloud and close all of its data centres. The sheer amount of data involved in Netflix’s workloads meant lifting and shifting simply was not an option, and it had to rearchitect its entire product. A business like Netflix could afford to invest the time and money involved in this process — while also allowing its product to evolve rapidly.

Over the course of its seven-year migration, the video streaming service’s subscriber base has increased 10 times, spreading across a steadily increasing number of target platforms and compatibility with many different devices. Netflix’s approach to migration came at the right time. Supporting such rapid growth in viewership and its availability on an increasing variety of devices would have been extremely difficult if it were not for the rearchitecting cloud migration strategy it utilised.

Soon after Netflix migrated to the cloud, the streamer also went global, expanding its services to 130 countries. It made use of cloud data centres based all over the world to support its global infrastructure capacity.

The Strangler Pattern: An Alternative Approach

An additional method worth mentioning — albeit one technically falling under the rearchitecting category — is the strangler pattern. In this cloud migration approach, an organisation’s original legacy system is put behind an intermediary façade while engineers refactor key applications. Over time, the newer system replaces the legacy infrastructure.

However, if things go wrong, there will be a great deal of difficulty involved in rolling back each refactored instance. Therefore, this is not the best approach for a company with limited resources.

Which Strategy is Right for You?

No matter what, when choosing a migration method, you will have to take into account the IT budget of your organisation, as well as the architecture and design patterns of your existing applications. With that said, given the ultimate limitations of the lift and shift method, Ballard Chalmers’ experts will often advise against it, or minimally a lift and shift followed by immediate modernisation.

To learn more about successful examples of application rearchitecting across widely varying verticals, take a look at any of the following case studies:

Transparity Ballard Chalmers can help you migrate to the cloud in whichever way suits you best. Get in touch or call us on 01342 410223.

Post Terms: Cloud Migration | Lift and shift | Migrating to Azure | Rearchitecting

About the Author

Our technical team contribute with blogs from their respective specialities, be that Azure, SQL, BizTalk, SharePoint, Xamarin and more. From the lead architect to developers and testers, each person provides content straight from their experience.

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