- [Instructor] Hello and welcome back. In this lecture we are going to learn how to recognize and explain the Six Rs, or the Six Common Strategies, used when discussing Cloud Migration projects. In 2011, Gartner Group outlined five common migration strategies, which provided a great benchmark for discussing and defining migration strategy in the early days of public cloud adoption. Over the fullness of time that has evolved into six definitions, which were commonly used when discussing migration to Cloud services. They're commonly called the Six R's and they are Rehost, Replatform, Repurchase, Refactor, Retain and Retire. Let's work through these six strategies, so we're clear on the operational benefits and the business merit of each construct. Just before we start, let's just reaffirm that every migration is going to be unique and that these strategies are not meant to be definitive or mutually exclusive. They should be used as guidelines and discussion starters only, something that can be very helpful when you are running a Cloud transformation workshop or a brainstorming session. And as we will see with the Expertise Please migration project, a migration project can easily include elements of all of these strategies at various stages. So first cab off the rank is Rehost, commonly referred to as lift and shift. Now lift and shift is generally as it sounds. Lifting servers or applications from the current hosting environment and shifting them to infrastructure in the public Cloud. Rehosting and the lift and shift is a very common strategy for organizations starting out on their migration journey. There are significant benefits in running servers on the scalable, pay as you go infrastructure of a public Cloud platform. So it is a relatively low resistance migration strategy and this is a great strategy for working backward from a fixed constraint or a hard deadline. In practice, the application or server will be exported via a third party export tool like VMware's V Center, for example, or created as an image that can be exported to a compute instance or container run on a Cloud compute service. Containerized applications make this process a relatively simple exercise as the operating environment is included in the container's schema. If you are running a monolithic application, then this rehosting can again be a simple way of getting started with Cloud services. Second cab off the rank is Replatforming which is to modify lift and shift. Replatforming involves making some optimizations to the application during the migration stage. So the third R is to Repurchase which is sometimes referred to as drop and shop. And this refers to the decision to move to another product. This may mean ending existing licensing and repurposing services on a new platform or service. Examples of this may be a CRM system or an industry specific application not designed to run on Cloud infrastructures. Now this is often not necessary with bespoke applications written with modern application code as with modern code it is possible to transport the code from one provider to another. The Repurchase strategy is often applied when using a proprietary database platform or proprietary product. Our fourth R is Refactorng or rearchitecting and this strategy is usually driven by a strong desire to improve services. Drivers for this might be that it is difficult to make improvements in the current environment or it may be a requirement to improve availability and reliability immediately, say to meet a specific security or compliance requirement. With refactoring, much depends on the nature of the service you want to refactor. If it is not a mission critical service, then it may be possible to rearchitect a service as required during the migration stage. Refactoring is feasible during the first phase of a migration if you do not have a time constraint. Otherwise, it is most likely better done at a later phase of the project. Okay, so strategy number five is to Retain. You may want to retain portions of your IT portfolio because there are some applications that you are not ready to migrate and feel more comfortable keeping them on premise. With this use case it may make sense to retain aspects of your IT services in the current environment and implement a hybrid or part migration strategy. So this approach makes sense if current regulatory or constitutional rules require you to store or run some aspects of your services or business application on premise or within specific regions. So that brings us to strategy number six which is to retire services. Now this strategy involves identifying assets and services that can be turned off so the business can focus on services that are widely used and of immediate value to the business. So that brings us to the end of our brief summary of the 6 Common Migration Strategies.