3 best practices for large-scale AWS migrations

3 best practices for large-scale AWS migrations

AWS migration best practices may include taking a structured migration approach, choosing the right toolset, and establishing an AWS cloud migration factory.

Published May 22, 2024
As of 2024, Amazon Web Services (AWS) remains one of the most popular cloud platforms, with the highest relative market share (50.1%) among the top ten global cloud providers, as revealed by the AWS Ecosystem in 2024 report by HG Insights. A vast and mature ecosystem of services is one of the reasons why many companies prefer implementing and migrating to AWS.
Migration can be especially advantageous for companies moving their on-premises workloads to AWS. Of those who did it, 66% noted reduced infrastructure costs and 43% faster time to market for new features, according to the Maximizing Economic Advantages by Migrating to AWS Cloud Infrastructure report from Enterprise Strategy Group.
However, the migration process can be challenging, especially if a company moves hundreds or more servers and applications to AWS. This article covers the challenges of large-scale AWS migrations and provides some best practices and tips for AWS migration to help companies switch to this cloud platform more smoothly.

What is large-scale AWS migration, and why is it challenging?

Amazon Web Services defines large-scale migrations as those involving the transfer of more than 300 servers and numerous app and database workloads from on-premises data centers to the AWS cloud infrastructure. Companies initiating and executing large-scale AWS migrations should be ready to face multiple challenges, including the following:
·         Migrating dependent entities
Each piece of software planned to be migrated can depend on other software, hardware, or shared databases. Therefore, migrating an application without a clear identification of all its dependencies can lead to various negative consequences, varying from software performance degradation to data corruption and loss.
While this challenge is typical for all cloud migration projects, it becomes particularly acute in cases of large-scale AWS migrations. For example, Deloitte mentions a client whose migrated systems had almost 100,000 application dependencies in one of its cloud migration case studies.
·         Ensuring data security
Data loss and other security violations that can potentially occur throughout and after the migration can result in significant financial costs and reputational damage and should, therefore, be avoided. IBM's Cost of a Data Breach Report 2023 states that the global average cost of a data breach reached $4.45 million in 2023, while 82% of these security breaches involved data stored in the cloud.
·         Avoiding AWS migration costs overrun
Even a small cloud migration project can involve different types of financial expenses and cost thousands of dollars, not to mention complex, large-scale migrations. Without an adequate assessment of all migration costs, including the hidden ones, a company can face a significant budget overrun and fail to achieve the desired AWS migration ROI.

How to ensure smooth large-scale AWS migration?

These practices can help a company ensure the success of its large-scale AWS migration:

1. Executing migration with a three-phased approach

A structured and gradual approach to migration is critical, and apparently, large-scale AWS migration projects should be no exception. Companies can rely on the three-phased approach proposed by AWS for large migrations specifically. Here it is broken down:
Phase 1. Assessment 
During this first preparatory phase, the company should evaluate its overall readiness for AWS migration and take inventory of corporate assets that have to be migrated. This assessment allows a company to identify the scale of future migration more adequately, which in turn can help predict its cost more accurately.
In addition, the assessment allows a company to identify and map dependencies between its apps. This can help avoid technical errors and conflicts during the migration process and ensure cloud workload availability after the migration is completed.
Conducting a well-rounded and comprehensive assessment can be challenging, especially in large-scale AWS migration projects. To streamline this process and make it more manageable, companies can use the official AWS Cloud Adoption Framework (AWS CAF). AWS CAF allows a company to assess its cloud readiness from multiple perspectives:
  • Business (Will migrating to AWS help achieve our desired business goals?)
  • People (Do we have enough skills and competence to carry out the migration?)
  • Governance (Will we be able to minimize the risks and maximize the benefits of cloud transformation?)
  • Platform (Can we build flexible and scalable cloud-based solutions using the AWS platform?)
  • Security (Can we ensure data security and integrity during and after migration?)
  • Operations (Will the migration affect the efficiency of our workflows and operations?)
Phase 2. Mobilization
The company must then prepare and optimize its workloads for the AWS cloud, as well as prioritize them to determine which ones should be migrated first. In addition, this stage can include training an in-house IT team on how to operate with AWS services and tools and design the target cloud architecture.
Phase 3. Migration and modernization
Now, it is time to start moving the workloads to AWS. This stage should include migration testing, which helps determine whether functional and non-functional migration requirements are met.

2. Defining the right AWS migration toolset

Being complex in its nature, large-scale migrations can become much more manageable if a company uses the right AWS migration tools. The platform provides many types of services that can help streamline almost any aspect of AWS migration.
For example, AWS Migration Hub enables managing the migration end-to-end. With its help, companies can discover their workloads and dependencies between them, develop tailored migration strategies and plans, and monitor migrations to ensure they go as planned.
Another tool, AWS Migration Evaluator, allows businesses to determine the financial value of large-scale migration to AWS. With this service, companies can assess their computing resources to predict migration costs. In addition, it allows companies to compare the cost of bring your own license (BYOL) and license included (LI) AWS pricing options.
AWS Snow Family is one more solution that can be useful for large-scale migrations. It allows companies to move large amounts of data (up to multiple petabytes) into the AWS platform faster and keep this data secured by using 256-bit encryption keys that can be managed via the AWS Key Management Service (KMS) console.

3. Establishing an AWS migration factory

A migration factory represents a collection of tools, processes, and people that operate in conjunction based on a factory-line approach to provide efficient and smooth migration of a large number of workloads to AWS. The AWS migration factory approach usually implies creating a dedicated cloud migration team consisting of cloud architects, DevOps engineers, and cloud security engineers within an organization to enhance the effectiveness of the approach.
Typically, such a dedicated team advocates an iterative migration approach. Initially, the team moves minor and less critical workloads, gaining experience, and only then proceeds with the remaining critical workloads using proven automation patterns. This way, companies can standardize and accelerate large-scale migrations while reducing  costs.

Final thoughts

Despite all the potential benefits of migrating to Amazon Web Services, the migration process itself can be very complex, especially if a company is moving hundreds of servers and apps and large amounts of data to AWS. A company has to identify all dependencies between its apps, ensure the security of migrated data, and also calculate the migration cost accurately.
To mitigate many challenges of large-scale migrations, companies can rely on suitable AWS migration best practices. These may include taking a structured migration approach, choosing the right toolset, and establishing an AWS cloud migration factory.
If a company lacks the required expertise to carry out the migration, professional third-party AWS consultants can augment its in-house team to help identify the hidden risks of large-scale migrations and craft tailored migration strategies.