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Database Migration: Overview & Types

Database Migration: Overview & Types

Your business is growing rapidly, and your current database is struggling to keep up with the increasing data storage and processing demands. You know it's time for a change, but the thought of migrating your database to a new system feels like a daunting task. You worry about data loss, extended downtime, and the potential impact on your business operations. 

If you're facing the challenge of database migration, you're not alone. Many organizations find themselves in a similar situation as they navigate the ever-evolving landscape of data management. 

In this blog post, we'll dive into database migration, exploring the fundamentals, architecture, and key considerations. We'll also discuss various migration strategies and provide a step-by-step guide to help you plan and execute your migration with confidence. So, whether you're a business owner, IT manager, or database administrator, this blog post will help you demystify database migration and empower you to make informed decisions for your organization's data future.


What is Database Migration?

Database migration involves transferring data from one database system to another. This process can be within the same environment (homogeneous migration) or across different environments (heterogeneous migration). The goal is to optimize performance, scalability, and flexibility, often by leveraging the capabilities of cloud services like AWS.


The Basics of Database Migration

Understanding How Database Migration Works

Database migration is not just about moving data; it's about transforming and restructuring it to fit the new environment. This process often includes data extraction, transformation, and loading (ETL), ensuring data integrity and consistency throughout the migration.

First, let’s begin by identifying and defining some key terms.


Key Terms You Should Know

  • ETL (Extract, Transform, Load): The process of extracting data from one source, transforming it to fit operational needs, and loading it into the target database.
  • Homogeneous Migration: Moving data between similar database systems.
  • Heterogeneous Migration: The transfer of data between different types of database systems.
  • Amazon RDS (Relational Database Service): A managed relational database service provided by AWS that simplifies database setup, operation, and scaling.
  • Amazon S3 (Simple Storage Service): AWS's scalable storage service used for storing and retrieving large amounts of data.
  • Amazon EC2 (Elastic Compute Cloud): A web service that provides resizable compute capacity in the cloud, enabling easy scalability of applications.
  • Amazon IAM (Identity and Access Management): A service that helps securely control access to AWS services and resources for users.
  • AWS Lambda: AWS's serverless compute service that runs code in response to events and automatically manages the compute resources.
  • AWS CloudFormation: A service that helps model and set up AWS resources so that you can spend less time managing those resources and more time focusing on your applications.
  • Amazon VPC (Virtual Private Cloud): A service that lets you launch AWS resources in a logically isolated virtual network that you define.
  • Amazon DynamoDB: A managed NoSQL database service provided by AWS that offers high performance, scalability, and reliability.
  • Amazon Redshift: AWS's fully managed data warehouse service that allows for fast querying and analysis of large datasets.
  • AWS Glue: A fully managed ETL service that makes it easy to prepare and load data for analytics.
  • AWS Elastic Beanstalk: An easy-to-use service for deploying and scaling web applications and services.
  • AWS CloudTrail: A service that enables governance, compliance, and operational and risk auditing of your AWS account.
  • AWS Scaling: A service that automatically adjusts the number of EC2 instances to handle the load for your application, ensuring optimal performance and cost efficiency.
  • Amazon Aurora: A MySQL and PostgreSQL-compatible relational database built for the cloud, combining the performance and availability of high-end commercial databases with the simplicity and cost-effectiveness of open-source databases.

Types of Database Migrations Explained

Replication vs. Migration

  • Replication: Copying data from one database to another, typically for redundancy and disaster recovery.
  • Migration: The complete transfer of data from one database system to another, often involving data transformation.

Partial vs. Complete Migration

  • Partial Migration: Moving only a subset of data, often used for phased migration or pilot projects.
  • Complete Migration: Transferring all data from the source to the target database.

Heterogeneous vs. Homogeneous Migration

  • Heterogeneous Migration: Involves different database technologies, such as moving from an Oracle database to a PostgreSQL database.
  • Homogeneous Migration: Involves similar database technologies, such as migrating from one MySQL database to another MySQL database.

What is Database Migration Cardinality?

Cardinality in database migration refers to the relationship between data elements in different sets. Understanding these relationships is crucial for maintaining data integrity during the migration process. For example, a one-to-many relationship, such as a single customer with multiple orders, needs to be preserved to ensure the accuracy of the migrated data.

Properly handling cardinality helps in optimizing queries and maintaining the performance of the new database system. Utilizing AWS services such as Amazon RDS and AWS DMS can help manage and preserve these relationships effectively during the migration.


Architecture of Database Migration

Explaining the Setup for Database Migration

Setting up for database migration involves careful planning and execution to ensure a smooth transition. 

Here are the key steps involved:

  1. 1. Selecting the Source and Target Databases:
  • Identify the databases you are migrating from and to. This could involve moving from on-premises databases to cloud-based solutions like Amazon RDS, Amazon Aurora, or Amazon DynamoDB.
  1. 2. Choosing Appropriate AWS Migration Tools:
  • AWS Database Migration Service (DMS): For replicating and migrating databases with minimal downtime.
  • AWS Schema Conversion Tool (SCT): To convert database schema and code from the source database to a format compatible with the target database.
  • AWS Snowball: For large-scale data transfers where network bandwidth is a limiting factor, using physical devices to move data into AWS.
  1. 3. Configuring the Necessary Network Settings:
  • Ensure that the network settings are properly configured for secure and efficient data transfer. This includes setting up Virtual Private Cloud (VPC) peering connections, configuring security groups, and ensuring proper firewall settings to allow seamless data flow between the source and target environments.
  1. 4. Implementing Security Policies:
  • Implement robust security measures to protect data during migration. This includes using encryption for data in transit and at rest, managing permissions through AWS Identity and Access Management (IAM), and conducting regular security audits.
  1. 5. Setting Up Monitoring and Logging:
  • Use AWS CloudWatch and AWS CloudTrail to monitor the migration process and log activities. This helps in tracking progress, identifying issues, and ensuring compliance with security policies.
  1. 6. Testing the Migration Setup:
  • Conduct thorough testing of the migration setup before the actual migration. This involves performing trial runs, validating data integrity, and ensuring that the target environment can handle the expected load.
  1. 7. Planning for Rollback Scenarios:
  • Prepare for potential rollback scenarios in case of issues during migration. This includes having a backup of the source database and a clear plan for reverting changes if needed.

By following these steps and utilizing AWS services effectively, you can ensure a secure, efficient, and successful database migration process.


What Tools and Systems You'll Need

To execute a successful database migration, you'll need the right tools and systems in place. AWS offers a comprehensive suite of services designed to simplify and automate the migration process. We mentioned a few tools in the section above, but let's take a closer look at some essential tools you'll need for your database migration journey.

Database migration tools like AWS Database Migration Service (DMS) can automate and streamline the migration process, reducing downtime and ensuring data integrity. AWS DMS supports both homogeneous and heterogeneous migrations, making it versatile for various migration needs.

Additionally, AWS Schema Conversion Tool (SCT) helps convert your database schema to a format compatible with the target database, simplifying complex migrations. For data integration and transformation, AWS Glue offers a fully managed ETL (Extract, Transform, Load) service that makes it easy to prepare and load data for analytics. Another valuable tool is Amazon S3, which can be used to store and transfer large datasets securely during the migration process. Utilizing these AWS tools ensures a seamless and efficient database migration.


Using Built-in Features of Database Management Systems

Many database management systems offer built-in features that can simplify and streamline the migration process. Amazon RDS (Relational Database Service) provides tools for snapshot and replication-based migrations, which help minimize downtime and data loss. Additionally, the AWS SCT is invaluable for converting your database schema from one database engine to another, facilitating complex migrations.

Amazon Aurora, with its high availability and automated backup features, also simplifies the migration process, ensuring data integrity and reducing administrative overhead. Utilizing these built-in features of AWS database management systems can streamline your migration efforts and ensure a smooth transition.

In some cases, off-the-shelf tools may not meet specific migration needs, requiring custom solutions tailored to the unique requirements of the business. We recommend that you consult with an AWS Premier Tier Partner for more information on a custom solution for your business.


What to Consider During Database Migration

How Migration Downtime Impacts Your Business

Minimizing downtime during a database migration is crucial to ensure business continuity and maintain a positive customer experience. Extended periods of downtime can lead to lost revenue, decreased productivity, and damaged reputation with your customers. In today’s on-demand era, customers expect 24/7 access to services, and any interruption can cause major frustration.

To mitigate the impact of migration downtime, it's essential to plan and execute the migration strategically. One approach is to use a phased migration, where data is transferred incrementally, allowing for shorter periods of downtime. This method enables you to migrate critical data first, followed by less essential data, reducing the overall impact on business operations.

Another effective strategy is to use replication for live systems. By setting up real-time replication between the source and target databases, you can keep both systems in sync during the migration process. This allows for a smooth transition with minimal downtime, as the target database is continuously updated with the latest changes from the source database.

In addition to these strategies, it's crucial to communicate with stakeholders and customers about any planned downtime. Providing advance notice, scheduling migrations during low-traffic periods, and having a clear communication plan can help manage expectations and minimize the impact on end-users.


Ensuring Data Consistency Throughout the Migration Process

Ensuring data consistency is one of the most critical aspects of a successful database migration. Inconsistent data can lead to inaccurate insights, flawed decision-making, and a loss of trust in the system. To maintain data integrity throughout the migration process, it's essential to employ robust data validation and reconciliation techniques.

Data validation involves verifying the accuracy, completeness, and format of the data being migrated. This process helps identify any discrepancies, such as missing or duplicated records, incorrect data types, or inconsistent formatting. By validating the data at various stages of the migration, you can catch and rectify errors early, preventing them from propagating to the target database.

Data reconciliation is another crucial technique for maintaining consistency. It involves comparing the data between the source and target databases to identify and resolve any discrepancies. This process can be performed at various levels, such as row counts, data values, or aggregated results. By reconciling the data, you can ensure that the target database accurately reflects the source data.


Other Important Factors to Consider

Compliance and Security

Ensuring compliance with data protection regulations and securing data during migration is paramount. Encrypting data in transit and at rest, and conducting regular security audits are best practices.

Compatibility with Existing Systems

Ensuring the new database system is compatible with existing applications and systems is essential for a smooth transition.

Dealing with Data Transformation and Schema Mapping Challenges

Data transformation and schema mapping can be complex, especially in heterogeneous migrations. Tools like AWS Schema Conversion Tool can automate and simplify this process.


Planning and Executing Migration

Step-by-Step Guide for a Successful Migration

1. Assessment: Evaluate the source and target databases and plan the migration strategy.

2. Preparation: Set up the migration environment and tools.

3. Execution: Perform the migration, ensuring minimal downtime and data consistency.

4. Validation: Validate the data in the target database and resolve any discrepancies.


Real-Life Example of a Successful Database Migration

‍After acquiring a company, mPulse Mobile needed support migrating the acquisition from an Oracle database on Rackspace to AWS. The company did not have the internal bandwidth to execute a migration of this magnitude – the 400+ gigabyte production database, being written to every single second, was both high volume and high velocity. The migration also needed to be completed with full HIPAA compliance.

Mission was brought in to migrate the healthcare technology company’s Rackspace-hosted Oracle database to AWS. Mission worked closely with mPulse for weeks, ultimately completing the migration with less than one hour of database downtime – well within mPulse’s requirements. mPulse calculates that the successful migration from Rackspace to AWS saves the company $10,000 every month – while also simplifying its infrastructure and HIPAA compliance.


Common Challenges in Database Migration & How to Solve them

Pitfalls in Database Migration

  • Underestimating Complexity: Not fully understanding the intricacies of the migration can lead to failures. Migration projects often involve unexpected challenges that can complicate the process.
  • Inadequate Testing: Skipping thorough testing can result in data loss or corruption. Without proper testing, issues may only become apparent in production environments, leading to downtime and data integrity problems.
  • Data Incompatibility: Differences in data formats, types, and structures between the source and target databases can cause compatibility issues, leading to data corruption or loss.
  • Insufficient Resources: Underestimating the resource requirements, such as compute, storage, and network bandwidth, can lead to performance bottlenecks and extended migration timelines.
  • Lack of Expertise: Insufficient knowledge about the source and target databases, as well as the migration tools and processes, can result in inefficient migrations and increased risk of errors.
  • Inadequate Backup Plans: Failing to create comprehensive backup plans before migration can result in irreversible data loss in case of migration failures.
  • Ignoring Downtime Impact: Not properly accounting for the impact of downtime on business operations can lead to significant disruptions and potential revenue loss.

Tips and Solutions to Tackle Challenges

  • Thorough Planning: Detailed planning and assessment can mitigate many migration challenges. Create a comprehensive migration strategy that includes timelines, resource allocation, risk assessment, and rollback plans.
  • Using Experienced Professionals: Leveraging the expertise of professionals can ensure a smooth migration process. Experienced teams can anticipate potential issues and address them proactively.
  • Extensive Testing: Conduct thorough testing before, during, and after the migration. This includes validating data integrity, performance testing, and simulating real-world scenarios to identify and fix issues.
  • Automating Processes: Utilize automation tools provided by AWS, such as AWS DMS and AWS SCT, to streamline the migration process and reduce human error.
  • Ensuring Compatibility: Use tools like AWS SCT to convert and optimize database schemas, ensuring compatibility between the source and target databases.
  • Adequate Resource Provisioning: Ensure that sufficient compute, storage, and network resources are allocated for the migration. Monitor resource usage and adjust as needed to avoid bottlenecks.
  • Robust Backup Plans: Implement comprehensive backup plans and regularly test them. This ensures that you can recover data in case of migration failures.
  • Communication and Training: Keep all stakeholders informed about the migration process, timelines, and potential impacts. Provide training for the team on the new system and tools.
  • Continuous Monitoring: Use AWS CloudWatch and AWS CloudTrail to continuously monitor the migration process, identify issues in real-time, and take corrective actions promptly.
  • Incremental Migration: Consider an incremental or phased migration approach to minimize risks. Start with non-critical data and systems to validate the process before migrating critical workloads.


Database migration is a complex but essential process for modern businesses. By understanding the basics, types, and best practices, companies can effectively migrate their databases, ensuring minimal downtime and data integrity. For more information or assistance with your database migration, contact Mission Cloud.

Contact Mission Cloud

Ready to migrate your database with minimal downtime and maximum efficiency? Get in touch with Mission Cloud today and let our experts guide you through a seamless migration process.

Author Spotlight:

Olivia Martinez

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