Every day, more IT organizations decide to move their SQL Server databases to Azure. In fact, over a million on-premises SQL Server databases have been moved to Azure. There’s an interesting blog about how Microsoft is faster and cheaper than its competitors that’s worth a read. To assist with your move to Azure Microsoft offers a number of migration tools and services to make this move as smooth as possible which I think attributes to their success. Two of those options are below with some informational links.
If you’re migrating a number of large SQL Server instances, Azure Database Migration Service is the best way to migrate databases to Azure at scale.
You can also automate the database migrations using the Azure Database Migration Service PowerShell commands.
Azure Database Migration Service (DMS) is a fully managed service for migrating multiple database sources to Azure data platforms at scale. It supports SQL Server 2005 through SQL Server 2019, as well as a variety of other source-target pairs. Azure DMS enables a seamless migration with minimal downtime or effort.
Let’s see how it works.
Working with Azure Database Migration Service
A typical database migration using Azure Database Migration Service consists of the following steps:
- Perform a migration assessment using Data Migration Assistant (DMA). Note any migration blockers that DMA reports and perform recommended remediations.
- If you need to assess the whole data estate and find the relative readiness of the databases migrating to Azure SQL, follow the steps provided here.
- Once you find the Azure SQL target, use Azure Database Migration Service to find the optimal Azure SQL target SKU that meets your performance needs.
- Create your target databases.
- Create an instance of Azure Database Migration Service.
- Create a migration project specifying the source databases, target databases, and the tables to migrate.
- Start the full load. Note: Select Online mode to include transaction log backups.
- Pick the subsequent validation.
- Perform a manual cutover of your production environment to the new Azure database.
Offline vs. Online Migration
The amount of downtime required to move to the cloud is always an important aspect in the decision to move to the cloud or not. Azure Database Migration Service allows you to do either an offline or online migration. The difference is the amount of downtime. With an offline migration, downtime begins at the same time that the migration starts. With an online migration, downtime is limited to the time required to cut over to the new environment at the end of the migration.
Microsoft recommends testing an offline migration. If you can’t tolerate the downtime, then switch to an online migration. It’s important to note, an Online migration requires an instance from the Premium pricing tier. However, they make it easy for you by offering it free for the first six months.
Summary
Azure Database Migration Service gives you a much better idea of what to expect when migrating large database instances at scale. It migrates your databases with ease using Microsoft’s best practices. Even better is that Microsoft continually invests in migrations by working to improve reliability and performance, as well as adding source/target pairs. I can easily see why they continue to lead in cloud technologies.
To learn more about moving your databases to the cloud, here is a great resource. “Future-Proof Your Data Infrastructure with Azure: A Business Case for Database Administrators.“