Migrating to Azure SQL Managed Instance

Learn how to effectively migrate your on-premises SQL Server databases to Azure SQL Managed Instance, a fully managed cloud database service that provides compatibility with SQL Server.

Introduction to Azure SQL Managed Instance Migration

Azure SQL Managed Instance (MI) offers a high degree of SQL Server compatibility, making it an ideal target for lift-and-shift migrations. This guide outlines the key considerations, strategies, and tools for a successful migration.

Key Benefits of Migrating to Azure SQL MI

  • High Compatibility: Minimizes application code changes.
  • Managed Service: Reduces operational overhead for patching, backups, and high availability.
  • Security: Built-in advanced security features.
  • Scalability: Easily scale resources up or down as needed.
  • Hybrid Capabilities: Supports hybrid scenarios with Azure Arc.

Migration Strategies

Several strategies can be employed for migrating to Azure SQL Managed Instance, depending on your downtime tolerance and complexity.

1. Online Migration

This approach minimizes downtime by continuously synchronizing data from the source to the target while the application remains online. It's suitable for mission-critical applications.

  • Tools: Azure Database Migration Service (DMS), Transactional Replication.
  • Process: Initial load, continuous synchronization, cutover.

2. Offline Migration

This strategy involves taking the source database offline during the migration process. It's simpler but requires a longer downtime window.

  • Tools: Backup and Restore, BACPAC files, Azure Data Factory.
  • Process: Backup source, restore to Azure SQL MI, configure applications.
Tip: Always perform a pilot migration with a representative subset of your databases to identify and resolve potential issues before a full production migration.

Azure SQL MI Migration Tools

Microsoft provides a suite of tools to facilitate your migration journey:

  • Azure Database Migration Service (DMS): A fully managed service that enables seamless migrations from multiple database sources to Azure data platforms with minimal downtime.
  • Azure Data Factory: A cloud-based ETL and data integration service that allows you to create data-driven workflows for orchestrating data movement and transforming data.
  • SQL Server Management Studio (SSMS): Offers features like the Data Migration Assistant (DMA) and direct backup/restore capabilities.
  • Azure Migrate: A central hub for discovering, assessing, and migrating on-premises applications and infrastructure to Azure.

Using Azure Database Migration Service (DMS)

DMS is the recommended tool for online migrations. Here's a high-level overview:

  1. Assess: Use the Data Migration Assistant (DMA) to assess your source databases for compatibility and identify any blocking issues.
  2. Create a DMS instance: Deploy an Azure DMS instance in your Azure subscription.
  3. Create a Migration Project: Configure the source and target connection details, and select the databases to migrate.
  4. Run the Migration: Start the initial data load and continuous synchronization.
  5. Cutover: Once synchronization is complete and you're ready, perform the cutover to redirect applications to Azure SQL Managed Instance.
Note: Ensure your Azure Virtual Network is properly configured to allow connectivity between DMS and your on-premises SQL Server instances.

Pre-migration Steps

Before initiating the migration, it's crucial to perform thorough preparation:

  1. Assessment: Identify all databases, their sizes, dependencies, and compatibility issues.
  2. Choose the Right Azure SQL MI Deployment Option: General Purpose vs. Business Critical.
  3. Network Configuration: Set up appropriate network connectivity (VPN, ExpressRoute) and firewall rules.
  4. Resource Provisioning: Provision the Azure SQL Managed Instance with adequate vCores and storage.
  5. Security Planning: Define authentication methods, access controls, and data encryption strategies.

Post-migration Tasks

After the data has been migrated and applications are pointed to Azure SQL MI, complete these tasks:

  • Performance Tuning: Monitor and optimize query performance.
  • Backup and Restore Validation: Verify that your backup and restore strategy is functioning correctly.
  • Security Review: Ensure all security configurations are in place.
  • Application Testing: Conduct comprehensive testing of all application functionalities.
  • Decommission Source: Once confident, decommission your on-premises SQL Server instances.

Best Practices

  • Start with a small, non-critical database for your first migration.
  • Document every step of the migration process.
  • Monitor resource utilization on both source and target environments.
  • Leverage Azure Hybrid Benefit for cost savings.
  • Stay updated with the latest Azure SQL MI features and migration tools.

For detailed step-by-step guides and advanced scenarios, please refer to the official Azure SQL Managed Instance documentation.

Last updated: October 26, 2023

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