Today, we will discuss 6 Rs of Migration Strategies. Stay tuned with us.
In many cases, cloud computing finds its way into companies through use in new projects. With migration, the benefits of cloud computing can be used not only for new but also for existing applications.
However, the effort involved in migration is often avoided because the risk is assessed too high and the benefit too low. With the right migration strategy, however, the risk can be minimized by performing the migration in small steps instead of in a large big bang project.
For this purpose, AWS has defined six migration strategies, also known as “the 6 Rs”. How these strategies are used and what advantages they bring will be examined in more detail below. It also discusses how to choose and apply the right migration strategy.
Why 6 Rs of Migration?
A migration allows the existing application to take advantage of the cloud. First of all, cost efficiency comes into play. The automatic scaling and the pay-per-use price model alone can reduce costs with little migration effort.
Also, a large part of the responsibility for the operation of the application and the maintenance of the infrastructure is outsourced to a cloud provider. The cloud providers specialize in providing the infrastructure and can therefore operate the application more cost-effectively compared to on-premises operations.
Another major advantage is the increase in agility during development. New features can be implemented more quickly through the use of cloud-native services. Infrastructure components are provided in the cloud within minutes. A quick “time to market” is a great advantage in competition. By automating the infrastructure with Infrastructure as Code, operational quality can even be increased while reducing costs.
6 Rs of Migration of Application To Cloud
The six strategies for migrating an application to the cloud were defined by AWS and are based on Gartner’s “5-R’s model”. The migration strategies of application include rehosting, re-platforming, repurchasing, refactoring, retain, and retire and can be used directly or building on one another.
With the repurchasing strategy, companies can switch from self-operated software to a cloud product – for example from a self-operated ticket or document management system to a software-as-a-service product (SaaS). The cloud provider assumes responsibility for the provision and operation of the software.
A major advantage is that the repurchasing strategy eliminates the need for the provision and maintenance of the infrastructure. Also, there is the fact that the transfer of inventory data from an old to a new system is usually supported by tools. As a result, the migration effort with this strategy is rather low.
The limitation of this strategy, however, is that only existing offers can be used. Adapting the software to your own needs is therefore only possible to a very limited extent. If a company only pursues the goal of reducing costs and focusing on its own core business, the repurchasing strategy is the way to go.
2. Rehosting – also known as “lift-and-shift”
The rehosting strategy aims to transfer applications from on-premises to the cloud without having to make adjustments. Besides, it is easy to use and can be largely automated with the help of tools. The strategy is particularly suitable for legacy applications that are difficult to adapt and for applications that have high scaling requirements.
Similar to the repurchasing strategy, the main goal is to save costs when operating the applications. Experience has shown that companies have been able to save up to 25 percent or more in operating costs in individual cases simply by moving to the cloud.
The replatforming strategy replaces as many components of an application as possible with cloud services without adapting the architecture. Hundreds of different services from cloud providers can be used. This includes typical components such as databases, messaging services, and storage services.
These components are often difficult to dimension, prone to errors, and require a lot of maintenance. However, these problems are solved by the services managed by the cloud provider. To keep the adjustment effort low, it is preferred to replace components for which there are similar services in the cloud. The main advantages of the 6 Rs of Migration strategy are the lower maintenance costs for the operation as well as the higher Scalability and the higher reliability of the application.
4. Refactoring – also called Rearchitecting
When using the refactoring strategy, the architecture of the application is also revised to use the full potential of the cloud. After applying the refactoring strategy, the application is a cloud-native application that supports the business model and continuous further development in the best possible way.
The refactoring strategy should be applied incrementally according to the basic principles of agile software development. This guarantees that the software will run at all times and that new features can be added during the cloud migration. Google calls the procedure “move and improve”.
With the refactoring strategy, as many components and services of the application as possible are outsourced to the cloud provider, because the latter specializes in the operation of these services. This reduces the maintenance effort for infrastructure components and more focus can be placed on the further development of the business model.
Retain and Retire are not migration strategies as such. The retain strategy is used when migration to the cloud does not bring increased benefits. In this case, the application continues to operate on-premises and is not migrated to the cloud.
The decision to use the retain strategy is not a final decision against migration. It should be checked regularly whether one of the other migration strategies should be used.
The Retire strategy of 6rs migration to cloud is used when the application is rarely used. In that case, the application is shut down to save operating and maintenance costs.
The End of 6 Rs of Migration Story
Choosing the right migration strategy is a balance between costs and benefits. The repurchase strategy offers the greatest benefit compared to the migration effort. It is therefore the first choice if there is a suitable software-as-a-service solution on the market.
However, the rehosting, replatforming and refactoring strategies can be used one after the other. With each strategy, the migration effort increases, but so does the benefit. Applying the strategies one after the other is helpful insofar as the subsequent migration strategies are then easier to apply.
The transfer of the application to the cloud should begin with the rehosting strategy, as the migration effort is manageable and cost-efficient.