Migrate model from AAS to Power BI without rebuilding reports.

Fabric, now has the capability to move the data model from Azure analysis Services to Power BI without rebuilding reports.But before getting to the steps, check for the below Prerequisites for the migration. 

Prerequisites:

 Azure Analysis Services (AAS) 

· The Azure Analysis Services server that you're migrating from and the Power BI workspace that you're migrating to must be in the same tenant.

· You must have Server administrator permissions and belong to the Owner and/or Contributor roles for the subscription.

· Azure Analysis Services must have an Azure Storage account with a container configured and backup enabled for the server as described in Azure Analysis Services database backup and restore.

· If Firewall is enabled for your server, ensure Allow access from the Power BI Service is set to On, or disable Firewall during migration.

· Your server must be started during migration. You can pause your server after migration is complete.

Power BI 

· To migrate to Power BI, you must have a Fabric Capacity (Formerly known as Premium per Capacity), Power BI Premium per User, or Power BI Embedded licence.

· You must have Workspace administrator permission. Power BI admins can view migrations for their tenant; however, they can't perform migrations unless they also have Workspace administrator permission.

· You must have an Azure Data Lake Storage Gen 2 (ADLS Gen 2) storage account in the same tenant and the workspace you're migrating to must be connected to that storage account. For the best performance, your ADLS Gen 2 storage should be in the same region as the workspace capacity.

· Large semantic model storage format must be enabled for the workspace.

· The XMLA endpoint must be Enabled for read-write for the capacity.

· If a Microsoft on-premises data gateway is configured for the Azure Analysis Services server to connect to on-premises data sources, you must also install and configure a gateway in Power BI. 

Let the Migration begin!

After ensuring prerequisites, begin a migration by first creating a connection between an Azure Analysis Services server and a workspace. The connection is a unique pairing between a server resource in Azure Analysis Services and a workspace in Power BI. Only one pairing connection can exist between a particular server and workspace.

How to Pair AAS and workspace:

1. In Power BI service, select Settings > Azure Analysis Services migrations.

2. On the Azure Analysis Services to Power BI Premium page, select + New Migration.

3. On the Create Azure Analysis Services migration flyout, select Connect to Azure.

4. Select the Azure Subscription, Resource group, and Server name with one or more model databases you want to migrate.

5. In the Workspace list box, select an existing workspace to migrate to or to create a new workspace, select Create a new Premium workspace, and then enter a workspace name, description, and select a licence mode.

6. For example, if creating a new migration connection with a new PPU workspace, the Create AAS migration flyout should look like the below image:

7. Verify your settings, and then select Create. 

Migrate

1. On the Azure Analysis Services to Power BI Premium page, select All migrations to refresh and show migration connection pairs created for your tenant.

2. Under Azure Analysis Services Server, select the server containing one or more model databases you want to migrate to the paired Power BI workspace.

3. In Migration Details, verify your Azure Analysis Services server and Power BI Premium workspace settings. Any prerequisites not met are shown. Model databases on the server that can be migrated are shown in Semantic models.

4. For each model database you want to migrate, under Include in Migration, toggle the slider button to Yes. 

Model databases are migrated in parallel, to reduce impact on your target capacity the maximum number of model databases that can be migrated concurrently is five.

5. Select Migrate.   

The migration process can take some time while the source model database is saved to backup storage, copied to ADLS Gen 2 storage, and restored to the workspace. You can leave this page and continue to use Power BI while migration is in process.

Server redirection isn't enabled during migration.To enable redirection, on the Azure Analysis Services to Power BI Premium page, under All migrations, for the migration pair you want to redirect, in the Server redirection enabled column, set the slider to Enable. 

You need to rebind the reports to query the model in Power BI.To rebind reports, on the Azure Analysis Services to Power BI Premium page, under All migrations > Azure Analysis Services server, select your server migration. Then, on the Migration details page, for your newly migrated model, select Rebind reports.

It's recommended you thoroughly test connecting to the migrated model in Power BI. 

Monitor migration.

On the Migration Details page, in Semantic models, select the model database you are migrating to show the Migration Details flyout. The flyout shows important details about your migration including status and migration progress.Pause server.

After you've verified a successful migration, you can pause your Azure Analysis Services server either in the Azure portal or by using the Azure Analysis Services REST API.

If your server remains started after you’ve enabled server redirection, existing Azure Analysis Services models can still be queried by setting the AsAzureRedirection connection string property to Disabled.

Reference : https://learn.microsoft.com/en-us/power-bi/enterprise/aas-pbi-migration-overview

Note: This blog post is based on the information available as of May 17, 2024. For the latest updates and details, refer to official Microsoft announcements and documentation.