How To Ensure Effective Data Migration Testing: Complete Guide

Data migration testing makes sure that the data was relocated with minimum disruption, without loss, and that all particular functions work correctly and meet system requirements. It is one of the most critical phases in the data migration process.

Many companies need to switch from outdated or inefficient software solutions to new ones, including data migration from on-premise to a cloud environment. In all cases, data can be migrated by specific tools or manually. There are also two important things to remember when running data migration testing. First, all changes are part of the new system. Second, you need to clearly understand the migration strategy to run a test.

Cprime ensures quality testing for clients in various industries. This article will share our thoughts and recommendations for data migration testing methodology, tools and strategic planning.

HOW TO PREPARE FOR DATA MIGRATION TESTING
The data migration process has three critical steps – extracting data, transforming data and loading data. Before we jump into the data migration testing strategy discussion, let’s define the crucial activity in the testing process.

Form a team. One of the most important things to have is a proficient data migration testing team with experience in your industry.
Outline migration scope. You need to analyze the range of migration data you need to test and the testing order.
Define business risks. You may need a Plan B for the case of finding critical mistakes during data relocation. It is also necessary to understand how testing affects the whole business process.
Choose a data migration testing tool. There are many tools for testing, but you should focus on specific ones to achieve your business goals.
Create testing documentation. To ensure efficient testing, you need to have a Migration Test Specialization. This document will include all critical things for the future process. It defines the data migration testing approach, methodology (i.e., black box or white box testing), testing cycles, environmental specifications and more.
Prepare for a testing launch. The last step will be to go through a data migration testing checklist and ensure that you are ready to run the process.
THE BEST DATA MIGRATION TESTING STRATEGY
After you learn the basics of data migration testing, you need to create an efficient strategy for the process. The testing strategy should be done in the following phases:

Pre-migration
Migration
Post-migration
PRE-MIGRATION TESTING STAGE
In relocating data for small projects, developers often skip this step. Besides, it is a required stage for data migration.

Here is a list of steps to follow for efficient pre-migration testing:

Clarify the scope of data that should be included, excluded or needs transformations. Analyze this scope before testing, then start the process with verification.
Analyze the new application data scheme. Learn how many mandatory fields it has, their types, length, and other parameters.
Define the destination and load processes. To ensure that you understand everything correctly, you should have a data dictionary or relationship diagram.
Launch data mapping between old and new applications. You need to compare each data type in the old system with a relevant data type in the new one.
Be sure that you have test cases and scenarios.
Check the configuration of data migration testing tools.
Review a set of cases with users and save the results. After the migration, you will need to check to ensure that legacy data and its functionality were not damaged.
Note the number of records in each table.
These are the basic steps that will help you get a clear understanding of the entire migration. In most cases, the quality of the pre-migration stage will influence the final testing.

MIGRATION TESTING STAGE
After completing the pre-migration testing checklist, it’s essential to ensure the testing during data relocation. The Data Migration Guide usually defines all process steps, and the testing team follows them. Ensure that there is a data backup to restore the old system at any time.

Migration Guide verification is also a part of the testing process. All migration steps should be included in the guide. This document should be clear and understandable.

The Migration Guide usually consists of the following documents:

Actual system migration
Hardware, software, port, firewall and other configurations that will be modified in a new application
Security check
Checklist of connections between all parts of the application
You need to note the actual migration time from the beginning to the time when you can relaunch the new system. This migration time should be added to the final test report. The report is critical of the Migration Test Result document you will prepare at the end.

Another thing you need to note during the migration process is system downtime. Generally, all system elements do not work during data migration. In ideal conditions, migration time and downtime would be the same.

What else should be tested in the migration stage? Migration script verification is an essential part of migration testing that you need to consider at this stage. Script scenarios can be different, and you will need to use white-box and black-box testing techniques.

After the data migration is done, you will launch basic tests to check the success of the relocation. All necessary tests should be defined before migration, and results noted in the Migration Test Specification. A lot of software can run on a few platforms. In this case, you need to ensure that data performs correctly on each platform.

POST-MIGRATION TESTING STAGE
After data has been relocated and you confirm that it was done successfully, it’s time to move to the last step – post-migration testing. This type of testing is usually performed in the test environment and includes the following steps:

Throughput migration testing. You require defining the number of records per unit time to calculate this. This step allows you to get an accurate time to complete the migration successfully.
Ensure the quality of migrated records. For this step, you compare migrated records to records from the destination system.
Compare migrated records to sources. It is crucial to identify that all field values are migrated according to specification.
Summary verification check. This type of testing will provide general information on the number of errors. It does not show where those mistakes were made. Also, this check will show if all the data was migrated. You need to compare the number of records between the old and updated systems to confirm this.
In addition to those necessary steps, there are additional migration data testing checks needed to ensure the quality of the process performed.

Here are some of them:

ensure data safety in a new application
check record integrity
ensure that the old functionality of a system works in a new one
create new users in the system to ensure its functionality with new data
run load and stress tests to ensure that the system is stable
There can be cases when the data is migrated without any changes. Then the testing goal is to verify the integrity of data. To do this, you can use sampling or any automated tools.

OTHER TYPES OF DATA MIGRATION TESTING
We have already described the most common way to launch a data migration test strategy. Types of testing during this process also include:

Backward compatibility testing. It is essential to ensure that a new system is compatible with an old one. To do it, you need to run special tests related to supporting backward compatibility.
Rollback testing. Something can go wrong in the migration process. That is why it’s crucial to have a migration failure test scenario as part of the negative testing and rollback mechanism. This test ensures that the migration did not affect the system and can work after rollback.
User acceptance data migration testing. It’s often difficult to identify problems with data migration in the early stages of the process. That is why it can benefit the company to allow the user community to interact with data before the product is released.
WHAT TO CONSIDER IN DATA MIGRATION TESTING
Lack of testing is usually the common reason for data migration failure. That is why we define the most critical things to consider in a test strategy for data migration.

Environmental. It is essential to understand the environment of data migration. You need to ensure that you can work in legacy and new environments. In this case, you can check data performance in the old system and the quality of migrated data. Those two databases need to work in parallel.

Data Migration Testing Approach. Consider a few different approaches in data migration testing before starting the process.

Data validation test. In this case, it is vital to create SQL queries to certify the data before and after migration.
Application-level validation test. In this approach, you should validate the functionality of a sample migration application.
Continuous support. It can communicate with clients when the system changes to ensure they have access to data and everything works appropriately. There is a need to provide some testing support even after the post-migration stage in most cases.

Documentation. Do not forget to complete the detailed required documentation on testing. For instance, it should be a migration test summary report after it is done. This document should include the following activities:

migration time
system downtime
how long it takes to migrate 10,000 records
rollback time
All the documentation will help with data migration in future system updates.

HOW TO DECREASE DATA MIGRATION TESTING RISKS
Below is some practical advice that will help reduce the risk with data center migration testing.

Use standardized data in your old system. In this case, all migrated data will be relocated correctly.
Increase the quality of data. It will help you to have better testing feel as an end-user.
Choose the best automation tool to ensure the quality of testing.
Recheck complex requests and constraints before running the testing.
Clean the data before migration. It is an essential step for data migration, and it helps you avoid duplicate data in the new system.
Ensure all system users have access to old and new databases without issues.
Involve stakeholders in data migration strategy planning. In some cases, permission to access different data sources will be necessary.

FINAL THOUGHTS
Testing the quality of data relocation is complicated, but it’s possible to run it efficiently without data loss. This article compiled the most effective practices in the testing process, explained the different types of testing, and hopefully guided you through every stage of the data migration test plan.

It is vital to have a reliable and experienced team to provide the testing. Cprime can offer any type of data migration. We have considerable experience on Jira/Atlassian projects. Our specialists can ensure testing quality and migrate legacy systems to new software applications or platforms. Contact us to discuss your data migration needs.