What is Application Migration?

Learning objectives
  • Explore migration best practices
  • Understand the 6 main migration strategies
  • Review the benefits of a successful migration

Application migration is the process of moving software from one environment to another. The process involves moving files, data (e.g., stored data in a database), and configurations from one location to another. As more enterprise organizations leverage cloud resources, migration of an application from on-premise servers to the cloud is common. Migration of an application is a complicated process, especially when it’s a critical part of productivity and downtime must be avoided. The aim for every organization is to have a smooth transition, but this requires good planning and testing prior to cutover. 

Why migrate an application to a new environment?

Organizations typically have several reasons to migrate an application to a new environment. One  common reason is due to poor performance and lack of resources to support additional users. Inefficient application resources impact productivity and the customer experience, so it’s often a primary factor in the decision to migrate. Migration to the cloud is a common approach to solving performance and resource issues; an application with a growing user base requires additional resources eventually, and the cloud scales much easier than building new resources onsite. 

The decision to migrate could be based on other factors including cost, elasticity, scale, and compliance. Data storage is virtually unlimited in a cloud environment, and some services (e.g., containerization) will scale up and down automatically, which gives organizations with seasonal business the resources to deal with traffic spikes. Using a provider with several data centers spanning multiple continents, international organizations can provide better application performance by distributing resources across targeted geolocated data centers for each country supported.

Finally, migration can be done for compliance reasons. For example, if the organization does not have the right monitoring and cybersecurity infrastructure on-premise, the application can be migrated to the cloud where its tools can be used to monitor and secure customer data.

What are migration strategy best practices?

Every organization wants to migrate their application smoothly and suffer from no downtime or bugs. Planning and testing are key to a smooth migration, but every team responsible for the migration faces challenges. By following best practices, the team should experience fewer bugs and less downtime.


The initial step in the migration process is planning. The planning process ensures that all resources and configurations for the application are accounted for. Every server, database, storage requirements, configurations, and users who need access to the application should be audited and included in the migration plan. 

Any interconnectivity between the migrated application and internal resources should be noted, because moving to another environment such as the cloud requires the right settings to continue communication between different environments. In some migrations, it could take refactoring code to support the change.

Thorough Testing

A good strategy is to go through a test run in a staging environment to get practice and identify any bugs before cutover to the production environment. The entire application data doesn’t need to be migrated during testing. A small subset of data along with files and configurations can be migrated to test the process.

After running a test migration, document any bugs or challenges so that they can be remediated before the final migration of production. This step is integral in a smooth transition from one environment to another, and it can greatly reduce the number of complications and downtime.


Some organizations migrate an application and think of security afterwards. For organizations that have concerns about compliance, cybersecurity should be a priority during migration. Cloud misconfigurations are a major factor in data breaches. For example, misconfiguring S3 buckets on Amazon Web Services (AWS) could expose all files and data stored there. Many organizations that use cloud services have a security expert review the setup for any misconfigurations and security flaws before going live.

Monitoring the Application

After migration, the application should be monitored so that bugs can be found and remediated quickly. Monitoring can also be used to identify bottlenecks and performance issues either from buggy code or failed resources. Using the right monitoring, you can identify downtime of specific application components, determine if more resources are needed, identify misconfigurations, and measure success by comparing previous application performance statistics with the new environment’s.

What are the 6 R’s of migration?

If you research application migration, you’ll find six strategies often referred to as the 6 R’s. For example, you might decide to migrate from a monolithic codebase to microservices. You could rebuild or replace the code to run in a cloud-native microservices environment. Here are the 6 R’s to help you find what’s right for your organization:

  • Rehosting: Referred to as a “lift and shift,” it’s the fastest way to migrate since it uses automation tools. It requires multiple testing rounds to ensure that automation is done properly, and it’s often used with legacy systems.
  • Refactoring: Refactoring is similar to rehosting, but it’s used when the application needs code changes to work in the new environment. It could be small code changes or a large refactoring effort.
  • Revision: Revision also requires refactoring changes to the code, but it adds infrastructure changes to the migration. This type of migration takes large amounts of effort to ensure that all changes are tested including configurations to the infrastructure hosting the new code.
  • Rebuild: In some scenarios, the application can’t be migrated. When revisions would just be too large, it’s sometimes more feasible to rebuild the application to work directly in the cloud. It can take years to rebuild a large business application, so this type of migration is only done when the organization has no other option and the application can no longer support current and future needs.
  • Replace: If any of the previous four migration types are not options, an out-of-the-box solution might be better suited for business requirements. Replacing an application with a new solution still involves migrating data and importing records to the target application.
  • Retain: After planning and testing, you might determine that migrating is the wrong choice. Retaining the current application can be done temporarily or while another solution is found to replace it.

What are the benefits of a smooth migration?

After migration, there can be a phase where bug fixes and user feedback seems overwhelming. Eventually, migration to a new environment to resolve the many bottlenecks and issues from the old environment will be realized, especially if the application is fully monitored. The benefits may not seem obvious in the beginning but after migration some benefits include:

  • Better productivity from employees who no longer have long wait times.
  • Better employee productivity from improved features.
  • Reduced resource usage and complexity from consolidation of applications (if migration involves multiple applications into one).
  • Better cybersecurity.
  • More modern environment for employees and customers.

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