Tutorial: Migrate SQL Server to an Azure SQL Database managed instance online using DMS

You can use Azure Database Migration Service to migrate the databases from an on-premises SQL Server instance to an Azure SQL Database managed instance with minimal downtime. For additional methods that may require some manual effort, see the article SQL Server instance migration to Azure SQL Database managed instance.

In this tutorial, you migrate the Adventureworks2012 database from an on-premises instance of SQL Server to a SQL Database managed instance with minimal downtime by using Azure Database Migration Service.

In this tutorial, you learn how to:

  • Create an instance of Azure Database Migration Service.
  • Create a migration project and start online migration by using Azure Database Migration Service.
  • Monitor the migration.
  • Perform the migration cutover when you are ready.

Important

For online migrations from SQL Server to SQL Database managed instance using Azure Database Migration Service, you must provide the full database backup and subsequent log backups in the SMB network share that the service can use to migrate your databases. Azure Database Migration Service does not initiate any backups, and instead uses existing backups, which you may already have as part of your disaster recovery plan, for the migration. Be sure that you take backups using the WITH CHECKSUM option. Also, make sure not to append multiple backups (i.e. full and t-log) into a single backup media; take each backup on a separate backup file. Finally, you can use compressed backups to reduce the likelihood of experiencing potential issues associated with migrating large backups.

Note

Using Azure Database Migration Service to perform an online migration requires creating an instance based on the Premium pricing tier.

Important

For an optimal migration experience, Microsoft recommends creating an instance of Azure Database Migration Service in the same Azure region as the target database. Moving data across regions or geographies can slow down the migration process and introduce errors.

Important

Reduce the duration of the online migration process as much as possible to minimize the risk of interruption caused by instance reconfiguration or planned maintenance. In case of such an event, migration process will start from the beginning. In case of planned maintenance, there is a grace period of 36 hours before migration process is restarted.

Tip

When you migrate databases to Azure by using Azure Database Migration Service, you can do an offline or an online migration. With an offline migration, application downtime starts when the migration starts. With an online migration, downtime is limited to the time to cut over at the end of migration. We suggest that you test an offline migration to determine whether the downtime is acceptable; if not, do an online migration.

This article describes an online migration from SQL Server to a SQL Database managed instance. For an offline migration, see Migrate SQL Server to a SQL Database managed instance offline using DMS.

Prerequisites

To complete this tutorial, you need to:

  • Create a Microsoft Azure Virtual Network for Azure Database Migration Service by using the Azure Resource Manager deployment model, which provides site-to-site connectivity to your on-premises source servers by using either ExpressRoute or VPN. Learn network topologies for Azure SQL Database managed instance migrations using Azure Database Migration Service. For more information about creating a virtual network, see the Virtual Network Documentation, and especially the quickstart articles with step-by-step details.

    Note

    During virtual network setup, if you use ExpressRoute with network peering to Microsoft, add the following service endpoints to the subnet in which the service will be provisioned:

    • Target database endpoint (for example, SQL endpoint, Cosmos DB endpoint, and so on)
    • Storage endpoint
    • Service bus endpoint

    This configuration is necessary because Azure Database Migration Service lacks internet connectivity.

    If you don’t have site-to-site connectivity between the on-premises network and Azure or if there is limited site-to-site connectivity bandwidth, consider using Azure Database Migration Service in hybrid mode (Preview). Hybrid mode leverages an on-premises migration worker together with an instance of Azure Database Migration Service running in the cloud. To create an instance of Azure Database Migration Service in hybrid mode, see the article Create an instance of Azure Database Migration Service in hybrid mode using the Azure portal.

    Important

    Regarding the storage account used as part of the migration, you must either:

    • Choose to allow all network to access the storage account.
    • Turn on subnet delegation on MI subnet and update the Storage Account firewall rules to allow this subnet.
  • Ensure that your virtual network Network Security Group rules don't block the following inbound communication ports to Azure Database Migration Service: 443, 53, 9354, 445, 12000. For more detail on virtual network NSG traffic filtering, see the article Filter network traffic with network security groups.

  • Configure your Windows Firewall for source database engine access.

  • Open your Windows Firewall to allow Azure Database Migration Service to access the source SQL Server, which by default is TCP port 1433.

  • If you're running multiple named SQL Server instances using dynamic ports, you may wish to enable the SQL Browser Service and allow access to UDP port 1434 through your firewalls so that Azure Database Migration Service can connect to a named instance on your source server.

  • If you're using a firewall appliance in front of your source databases, you may need to add firewall rules to allow Azure Database Migration Service to access the source database(s) for migration, as well as files via SMB port 445.

  • Create a SQL Database managed instance by following the detail in the article Create an Azure SQL Database managed instance in the Azure portal.

  • Ensure that the logins used to connect the source SQL Server and the target managed instance are members of the sysadmin server role.

  • Provide an SMB network share that contains all your database full database backup files and subsequent transaction log backup files, which Azure Database Migration Service can use for database migration.

  • Ensure that the service account running the source SQL Server instance has write privileges on the network share that you created and that the computer account for the source server has read/write access to the same share.

  • Make a note of a Windows user (and password) that has full control privilege on the network share that you previously created. Azure Database Migration Service impersonates the user credential to upload the backup files to Azure Storage container for restore operation.

  • Create an Azure Active Directory Application ID that generates the Application ID key that Azure Database Migration Service can use to connect to target Azure Database managed instance and Azure Storage Container. For more information, see the article Use portal to create an Azure Active Directory application and service principal that can access resources.

    Note

    Azure Database Migration Service requires the Contributor permission on the subscription for the specified Application ID. Alternatively, you can create custom roles that grant the specific permissions that Azure Database Migration Service requires. For step-by-step guidance about using custom roles, see the article Custom roles for SQL Server to SQL Database managed instance online migrations.

  • Create or make a note of Standard Performance tier, Azure Storage Account, that allows DMS service to upload the database backup files to and use for migrating databases. Make sure to create the Azure Storage Account in the same region as the Azure Database Migration Service instance is created.

Register the Microsoft.DataMigration resource provider

  1. Sign in to the Azure portal, select All services, and then select Subscriptions.

    Show portal subscriptions

  2. Select the subscription in which you want to create the instance of Azure Database Migration Service, and then select Resource providers.

    Show resource providers

  3. Search for migration, and then to the right of Microsoft.DataMigration, select Register.

    Register resource provider

Create an Azure Database Migration Service instance

  1. In the Azure portal, select + Create a resource, search for Azure Database Migration Service, and then select Azure Database Migration Service from the drop-down list.

    Azure Marketplace

  2. On the Azure Database Migration Service screen, select Create.

    Create Azure Database Migration Service instance

  3. On the Create Migration Service screen, specify a name for the service, the subscription, and a new or existing resource group.

  4. Select the location in which you want to create the instance of DMS.

  5. Select an existing virtual network or create one.

    The virtual network provides Azure Database Migration Service with access to the source SQL Server and target SQL Database managed instance.

    For more information on how to create a virtual network in Azure portal, see the article Create a virtual network using the Azure portal.

    For additional detail, see the article Network topologies for Azure SQL Database managed instance migrations using Azure Database Migration Service.

  6. Select a SKU from the Premium pricing tier.

    Note

    Online migrations are supported only when using the Premium tier.

    For more information on costs and pricing tiers, see the pricing page.

    Create DMS Service

  7. Select Create to create the service.

Create a migration project

After an instance of the service is created, locate it within the Azure portal, open it, and then create a new migration project.

  1. In the Azure portal, select All services, search for Azure Database Migration Service, and then select Azure Database Migration Services.

    Locate all instances of Azure Database Migration Service

  2. On the Azure Database Migration Service screen, search for the name of the instance that you created, and then select the instance.

  3. Select + New Migration Project.

  4. On the New migration project screen, specify a name for the project, in the Source server type text box, select SQL Server, in the Target server type text box, select Azure SQL Database Managed Instance, and then for Choose type of activity, select Online data migration.

    Create Azure Database Migration Service Project

  5. Select Create and run activity to create the project.

Specify source details

  1. On the Migration source detail screen, specify the connection details for the source SQL Server.

  2. If you haven't installed a trusted certificate on your server, select the Trust server certificate check box.

    When a trusted certificate isn't installed, SQL Server generates a self-signed certificate when the instance is started. This certificate is used to encrypt the credentials for client connections.

    Caution

    SSL connections that are encrypted using a self-signed certificate does not provide strong security. They are susceptible to man-in-the-middle attacks. You should not rely on SSL using self-signed certificates in a production environment or on servers that are connected to the internet.

    Source Details

  3. Select Save.

  4. On the Select source databases screen, select the Adventureworks2012 database for migration.

    Select Source Databases

    Important

    If you use SQL Server Integration Services (SSIS), DMS does not currently support migrating the catalog database for your SSIS projects/packages (SSISDB) from SQL Server to Azure SQL Database managed instance. However, you can provision SSIS in Azure Data Factory (ADF) and redeploy your SSIS projects/packages to the destination SSISDB hosted by Azure SQL Database managed instance. For more information about migrating SSIS packages, see the article Migrate SQL Server Integration Services packages to Azure.

  5. Select Save.

Specify target details

  1. On the Migration target details screen, specify the Application ID and Key that the DMS instance can use to connect to the target instance of Azure SQL Database managed instance and the Azure Storage Account.

    For more information, see the article Use portal to create an Azure Active Directory application and service principal that can access resources.

  2. Select the Subscription containing the target instance of Azure SQL Database managed instance, and then select the target instance.

    If you haven't already provisioned the Azure SQL Database managed instance, select the link to help you provision the instance. When the Azure SQL Database managed instance is ready, return to this specific project to execute the migration.

  3. Provide SQL User and Password to connect to the Azure SQL Database managed instance.

    Select Target

  4. Select Save.

Select source databases

  1. On the Select source databases screen, select the source database that you want to migrate.

    Select source databases

  2. Select Save.

Configure migration settings

  1. On the Configure migration settings screen, provide the following detail:

    SMB Network location share The local SMB network share or Azure file share that contains the Full database backup files and transaction log backup files that Azure Database Migration Service can use for migration. The service account running the source SQL Server instance must have read\write privileges on this network share. Provide an FQDN or IP addresses of the server in the network share, for example, '\\servername.domainname.com\backupfolder' or '\\IP address\backupfolder'. For improved performance, it's recommended to use separate folder for each database to be migrated. You can provide the database level file share path by using the Advanced Settings option.
    User name Make sure that the Windows user has full control privilege on the network share that you provided above. Azure Database Migration Service will impersonate the user credential to upload the backup files to Azure Storage container for restore operation. If using Azure File share, use the storage account name pre-pended with AZURE\ as the username.
    Password Password for the user. If using Azure file share, use a storage account key as the password.
    Subscription of the Azure Storage Account Select the subscription that contains the Azure Storage Account.
    Azure Storage Account Select the Azure Storage Account that DMS can upload the backup files from the SMB network share to and use for database migration. We recommend selecting the Storage Account in the same region as the DMS service for optimal file upload performance.

    Configure Migration Settings

    Note

    If Azure Database Migration Service shows error ‘System Error 53’ or ‘System Error 57’, the cause might result from an inability of Azure Database Migration Service to access Azure file share. If you encounter one of these errors, please grant access to the storage account from the virtual network using the instructions here.

    Important

    If loopback check functionality is enabled and the source SQL Server and file share are on the same computer, then source won't be able to access the files hare using FQDN. To fix this issue, disable loopback check functionality using the instructions here.

  2. Select Save.

Review the migration summary

  1. On the Migration summary screen, in the Activity name text box, specify a name for the migration activity.

  2. Review and verify the details associated with the migration project.

    Migration project summary

Run and monitor the migration

  1. Select Run migration.

  2. On the migration activity screen, select Refresh to update the display.

    Migration activity in progress

    You can further expand the databases and logins categories to monitor the migration status of the respective server objects.

    Migration activity in progress

Performing migration cutover

After the full database backup is restored on the target instance of SQL Database managed instance, the database is available for performing a migration cutover.

  1. When you're ready to complete the online database migration, select Start Cutover.

  2. Stop all the incoming traffic to source databases.

  3. Take the [tail-log backup], make the backup file available in the SMB network share, and then wait until this final transaction log backup is restored.

    At that point, you'll see Pending changes set to 0.

  4. Select Confirm, and then select Apply.

    Preparing to complete cutover

  5. When the database migration status shows Completed, connect your applications to the new target instance of Azure SQL Database managed instance.

    Cutover complete

Next steps