Table of Contents
Introduction
This tutorial guides you through the process of migrating your on-premises or cloud-hosted databases to Azure. Azure Database Migration Service (DMS) provides a comprehensive solution for migrating databases with minimal downtime. We will cover migrating a typical SQL Server database as an example, but the principles apply to other supported database types.
Prerequisites
Before you begin, ensure you have the following:
- An Azure subscription.
- Access to your source database (e.g., SQL Server, PostgreSQL, MySQL).
- Network connectivity between your source database and Azure.
- Necessary permissions to create resources in your Azure subscription.
- The Azure Data Migration Assistant (DMA) or Azure Migrate assessment tool installed for assessment.
Step 1: Prepare Your Source Database
1.1 Assess Your Database
Use Azure Data Migration Assistant (DMA) or Azure Migrate to assess your source database. This tool identifies potential compatibility issues and provides recommendations for schema and code remediation.
Download and install Azure Data Migration Assistant.
Follow the DMA wizard to connect to your source database, perform an assessment, and review the reports.
1.2 Remediate Compatibility Issues
Address any issues flagged by the assessment tool. This might involve modifying T-SQL code, stored procedures, or schema definitions to be compatible with your target Azure database service.
1.3 Back Up Your Database
Perform a full backup of your source database before starting the migration process. This is crucial for disaster recovery.
Step 2: Set Up Azure Resources
2.1 Create an Azure Database Instance
Provision your target Azure database service. This could be Azure SQL Database, Azure SQL Managed Instance, Azure Database for PostgreSQL, or Azure Database for MySQL.
Navigate to the Azure portal, search for your desired database service, and follow the creation wizard.
Example for Azure SQL Database:
az sql server create --name my-sql-server-unique --resource-group myResourceGroup --location westus --admin-user sqladmin --admin-password YourPassword123!
az sql db create --resource-group myResourceGroup --server my-sql-server-unique --name my-database --edition Basic --service-objective Basic --max-size 2 GB
2.2 Create an Azure Database Migration Service Instance
Azure Database Migration Service (DMS) orchestrates the migration. Create a DMS instance in the Azure portal.
Ensure the DMS instance is in the same region as your target Azure database and has network connectivity to your source database.
Step 3: Configure and Run the Migration
3.1 Create a Migration Project in DMS
Open your DMS instance in the Azure portal and click on "+ New Migration Project".
Choose the source and target database types, and the migration type (online or offline).
3.2 Configure Source and Target Details
Provide connection details for both your source database and your target Azure database instance.
Ensure the service account used by DMS has the necessary permissions on both ends.
3.3 Select Databases and Tables
Choose the specific databases and tables you wish to migrate.
3.4 Start the Migration
Once configured, review the settings and start the migration. Monitor the progress in the DMS portal.
For online migrations, DMS will set up continuous synchronization. For offline migrations, it will perform a one-time data transfer.
Step 4: Post-Migration Verification
4.1 Cutover (for Online Migrations)
When the synchronization lag is minimal, plan for a cutover. This involves stopping incoming traffic to the source database, ensuring all pending changes are replicated, and then redirecting your applications to the target Azure database.
4.2 Verify Data Integrity
Perform a series of checks to ensure all data has been migrated correctly.
- Compare row counts between source and target tables.
- Run sample queries against the target database and compare results with the source.
- Validate critical business logic and application functionality.
4.3 Update Application Connection Strings
Modify your application configuration to point to the new Azure database connection string.
4.4 Monitor Performance
Closely monitor the performance of your applications and the Azure database post-migration. Tune database settings and queries as needed.
Conclusion
Congratulations! You have successfully migrated your database to Azure. Azure Database Migration Service simplifies this complex process, enabling you to leverage the scalability, reliability, and advanced features of Azure's database offerings. Remember to explore Azure's monitoring and management tools to ensure the ongoing health and performance of your migrated databases.
For more advanced scenarios or specific database types, please refer to the official Azure Database Migration Service documentation.