legacy system migration

How to Undertake Legacy System Migration?

Estimated read time: 9 minutes

Are you interested in legacy system migration for your business software system?

According to a research report on cloud migration, the market for cloud migration services is expected to increase to 7.09 billion US dollars by 2024. Moreover, the data migration market is predicted to reach 10.98 billion US dollars by 2025.

The statistics show that the cloud computing industry is on a continuous rise, and it is high time for every business to keep up with technological advancements in order to stay ahead of the competition.

Let’s overview how you can carry out legacy system migration to a cloud infrastructure successfully.

How to Undertake Legacy System Migration Process?

Go through the following steps to undertake a legacy system migration:

1. Conduct a SWOT Analysis

As a first step, outline why a system migration is required and if it aligns with the business goals. The objective SWOT analysis should be conducted to analyze the strengths, weaknesses, opportunities, and threats of the migration exercise.

Such an analysis helps you plan multiple aspects and not just the technical process. It includes external dependencies, employee training, compliance factors, security procedures, etc.

The first stage would give you an overview of possible obstacles related to financial, operational, and staff training processes and help you proactively plan and manage them with minimum losses.

2. Assess Your Existing Infrastructure

The next important step is to assess and understand your existing infrastructure and legacy system. This involves going through all the components and related documents to understand their functionality in detail. 

In the case of a black-box system that has hidden functionality, analyze the inputs, outputs, and system responses. For white-box applications with transparent functioning, reverse engineering can be applied to understand system functions and related data effectively.


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The assessment of business processes, applications, etc., includes network architecture, performance requirements, related infrastructure, availability, etc.

Microsoft Azure, a cloud computing platform by Microsoft, for example, provides a Microsoft Assessment and Planning (MAP) Toolkit with inventory management and reporting capabilities.

MAP toolkit allows businesses to understand their physical and virtual environments before migrating to Azure. Moreover, it supports maintenance processes for new cloud migrations.

3. Select and Plan Your Legacy System Migration Strategy

Legacy system migration involves moving a software application to a different hardware infrastructure or software platform, preferably based on the latest technologies. Now, you should select the migration strategy for your legacy system.

You can opt for any approach from the following:

  • Lift and Shift: This method copies everything to the cloud. It does not involve a lot of effort to completely migrate a software system as it is. However, it may cause a waste of resources and unnecessary expenses for operations.
  • Application Evolution: This allows businesses to shift their legacy system to the cloud in chunks. The costs, however, remain high for this approach, where you identify software components you want on the cloud infrastructure.
  • Application-ReArchitecturing: This method breaks down the software application and rebuilds it in a more advanced and scalable way. It does not mean you are developing a software system from the ground up, instead, you undertake to revamp a codebase introducing more agility and enhancement in the business-related specifications.

Preparing a software application for a cloud can be a daunting process. Cloud service providers facilitate their customers with tools to help them go through the process of application rearchitecting smoothly.

For example, Microsoft Azure provides Azure Service Fabric to prepare a software system for the cloud through microservices.

If you analyze that your software system is performance-intensive, will work better on your current servers, has desktop integrations, etc., you can also adopt a hybrid cloud migration approach.

4. Choose Software Components to be Migrated First

If you plan on migrating your legacy system in components instead of the entire application, you need to decide which components or functionalities you want to migrate first.

Map out configurations for migration of the selected software components and also conduct an audit of these components. This will help you refactor your code according to the cloud environment. You will be able to get rid of components that do not serve any business value anymore. 

You will also find out interdependent components. Functionalities that depend on other functionalities and cannot be migrated alone. A mapping analysis will help you migrate such components with minimum disruption to business operations.

5. Prepare Your Cloud Infrastructure

As discussed above, depending on your adopted migration strategy, some applications just require a lift and shift of software application without much prior work to do. Some require figuring out components to migrate first, rearchitecting, etc.

For example, moving your corporate documentation to a SaaS service like Microsoft OneDrive does not require much effort. On another hand, you may require license renewals for some external software dependencies to use them on the cloud infrastructure, etc.

6. Evaluate Microservices

There are multiple cloud services available from various cloud service providers. You need to select services that meet your business needs and align with your business goals. 

Your migration plan, including project scope, requirements, potential issues, etc., help you go with the appropriate cloud service for your software system. 

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For example, depending on your industry, you have to follow certain regulations and make sure the cloud service you want to employ complies with the industry standards. 

Security is also a major concern when migrating to a cloud since cloud services are third-party services. You have to make sure that the cloud service provider provides you with enough data and system security certifications. You should be able to implement proper security authentication and encryption techniques.

7. Back up

Making a backup of your system is important as it helps to roll back to your previous system in case anything goes wrong with the migration plan.

8. Run and Test Your Pilot Migration

Now, you start with your test or pilot migration of your legacy system. A pilot migration of code helps you test your software system in a test environment that is closer to the actual environment your software application will run.

A pilot migration process takes effort and time as you need to do a lot of user testing, performance testing, etc., to prepare your software application code for the actual migration.

You should proactively remove all code bugs that can cause application downtime with actual migration in the real-time environment.

9. Migrate Legacy System Incrementally

Now that you have prepared and tested your system migration plan, you are ready to undertake your legacy system migration successfully. You start by backing up your data so that you do not lose anything during the migration. 

After migration, you conduct test procedures. You would test security, availability, and compliance.

You should also make sure all the existing data is present and users can access everything as required. Moreover, the data quality and data integrity is maintained as a result of successful data migration.

Migrating software applications in increments helps to test code effectively and resolve any issues that may arise at small levels. 

This is relatively easier than migrating the whole application at once and resolving multiple bigger issues that affect the smooth running of the application. Such bigger issues might require an extended downtime to resolve them.

Code bots are also used at this stage to write code in the cloud. After you have run a pilot migration routine, select the required cloud services, planned increments for system migration, etc., code bots can be employed to transfer code to the cloud faster than humans.

10. Manage Your New Cloud Infrastructure

After the complete migration of the existing systems to the cloud, you need to conduct a detailed analysis of the new software system, including the cloud infrastructure. You should make sure the cloud application is running as required at the user’s end. 

This may take several days for you to complete your system analysis and produce a performance report on new systems. In case problems arise, you can always contact your cloud service provider.

Regularly monitor the performance of your application, optimize cloud resources, and analyze the usage of these cloud system resources while tracking alerts and recommendations to improve the cloud resources.

For example, Amazon Web Services for cloud computing provides a cloud monitoring service called CloudWatch.

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It could help you collect monitoring and operational data such as logs, metrics, and events. It allows you complete visibility into your AWS cloud resources, applications, and services running on the AWS cloud or your site.

Planning a Legacy System Migration?

If your software system is hindering your business operations and the overall growth of your business, it is the right time to migrate your legacy system to a more developed and modern IT infrastructure.

Cloud infrastructure is getting popular rapidly, given the easy flexibility, scalability, and availability of advanced development, deployment, and hosting services it offers, in the form of SaaS, PaaS, and IaaS cloud computing resources.

It is worth mentioning that a legacy system migration is a crucial yet complex task. You have to get it right and with minimum expenses and efforts to ensure successful business continuity and delivery of business services to the user market.

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We recommend you partner with an experienced team of software developers to undertake this critical process and tackle legacy system migration challenges.

Your developers should be proficient in cloud computing and knowledgeable about the best cloud development and deployment practices, cloud security, data migrations, etc. 

If you do not find the required expertise in your software team, DevTeam.Space can help you via its field-expert software developers community. You can either hire these developers to support your current IT team or outsource your complete legacy system migration project to DevTeam.Space. 

All the developers at DevTeam.Space are vetted for their software development expertise and go through an elaborate screening process. You can rest assured that the top talent is migrating your legacy software.

You can easily partner with these software developers for your next software project by sending us your initial project specifications via this quick form.

One of our account managers will get in touch with you for your further assistance in getting onboard, planning your cloud migration project, etc.

Frequently Asked Questions on Legacy System Migration

1. What is legacy migration?

A legacy migration involves moving underperforming and outdated software systems or platforms from on-site servers to a modern cloud infrastructure. Migrating legacy systems becomes important when an existing system is causing unnecessary maintenance costs, giving limited functionality, compromising legacy data security, etc.

2. How do I migrate AWS legacy?

You can migrate legacy applications to the AWS cloud using the AWS App2Container service. AWS recommends a three-phase iterative migration process, including stages of Access, Mobilize, and Migrate & Modernize. It also has a comprehensive portfolio of data migration tools and libraries that help in the automation and overall simplification of the migration process, like data integration into the modern system, etc. Read more details here.

3. How do I migrate to legacy?

You can migrate a legacy application to a cloud by following a series of steps, including drawing up a legacy system modernization plan, choosing a migration strategy, deciding on the cloud services, running a pilot migration process followed by an incremental migration of the complete system, and finally, monitoring the performance of the new system and managing the cloud infrastructure.


Alexey Semeney

Founder of DevTeam.Space

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