How to Migrate from SSAS to Power BI: Step-by-Step Guide

Why Move from SSAS to Power BI?

Moving from SQL Server Analysis Services (SSAS) to Power BI (Semantic Models) is driven by the transition from a specialized on-premises technical tool to a cloud-scale business platform. 

• Unified platform: Power BI combines modeling (like SSAS Tabular) and data storage in one solution. It eliminates the need for separate licensing and infrastructure costs associated with SSAS.
• Cloud-First Analytics: Power BI integrates seamlessly with other Microsoft cloud services, while SSAS is an on-premise-focused solution. 
• Data Visualization and Interactivity: Power BI offers rich, interactive dashboards and reports that go beyond traditional SSAS reporting tools. Users can apply filters in real time and gain faster insights through intuitive visualizations.
• Seamless Integration: Power BI deeply integrates with Teams, SharePoint, and Excel, and other Microsoft services. This tight integration simplifies data connectivity and enhances collaboration across teams.
• Simplified deployment and Maintenance: Power BI gives regular updates and is easier to manage. With its built-in tools, they reduce the operational complexity compared to SSAS environments.

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Challenges faced during the SSAS to Power BI Migration and ways to overcome

SSAS to Power BI migration involves transitioning from a server-based architecture to a cloud-based semantic layer. Though SSAS Tabular shares the same engine as Power BI, there are significant hurdles in moving to SSAS Multidimensional. The core challenges and ways to overcome are 

• DAX calculations: Legacy MDX/ DAX queries might not translate directly or effectively. SSAS multidimensional models rely heavily on MDX, whereas Power BI supports DAX. To overcome this, identify critical MDX calculations and rewrite the logic using DAX in Power BI. Validate them thoroughly to ensure logic remains consistent after migration.
• Security and Role Mapping: Security is often handled in Windows Active Directory groups within a server instance. Row-level security (RLS) and role definitions in SSAS may not directly map to Power BI security models. To overcome this, we need to redefine security roles using Power BI RLS and thoroughly test access. 
• Performance: Large volumes of data in Power BI may result in slower refresh times. This causes a decrease in performance compared to optimized SSAS environments.
• Rebuilding reports: Existing reports from SSAS can be reused in Power BI. This leads to additional development effort. To mitigate this, prioritize high-value reports and start migrating them first using Power BI visuals and templates. Standardize report layouts to reduce redevelopment time.
• Cost: Power BI licensing (Premium) adds new costs compared to the on-premises SSAS deployments. To overcome this, access the required licensing, assess user counts, data refresh needs, and performance requirements. This will help in choosing the cost-effective Power BI licensing model. 

Best Practices for an SSAS to Power BI Migration

• Before starting with Power BI migration, audit the SSAS models, data sources, and dependencies.
• Prioritize the SSAS tabular models based on their usage and complexity.
• Standardize data sources before migration to avoid any performance issues.
• Reuse DAX calculations to optimize them for Power BI performance.
• Implement row-level security (RLS) to match existing SSAS access controls.
• In case of large data sets, configure for incremental refresh.
• Validate reports by comparing both SSAS and Power BI in parallel.
• Monitor the performance and optimize it continuously.

8 Step SSAS to Power BI Migration Process

Migrating SSAS to Power BI is more than lift and shift, and it requires modernization of the entire BI architecture.

1. Analyze SSAS Models:

Audit the existing SSAS models and analyze their architecture, including tabular or multidimensional models, data sources, DAX calculations, and security roles. Evaluate the complexity and data volume to determine Power BI Premium needs. Analyzing the SSAS models will help us identify compatibility gaps and any complexity in migration. Prioritize which reports to migrate first.

2. Set up Power BI environment:

Ensure that Power BI has Premium capacity and XMLA endpoints enabled. Configure data sources in Power BI. Choose the right migration approach based on business needs. Create a roadmap and define the scope and timelines.

3. Optimize Data models:

Validate data sources before starting the migration. Optimize queries, review refresh schedules, and ensure data models are structured for optimal performance.

4. Migrate Data models:

Connect to the SSAS instance and copy the SSAS metadata into the Power BI Workspace using an XMLA connection string. Change the model’s data source from a local provider to the gateway-supported connection in the Power BI service. SSAS Tabular models can be published directly into tabular format in Power BI.

5. Validate DAX calculations:

Reuse existing DAX measures and optimize them for Power BI performance. Adjust calculations to align with Power BI best practices and dataset limitations. 

6. Security and Governance:

Power BI security is robust. Update Row-level security (RLS) definitions and permissions in Power BI to maintain consistent data access. Ensure that it is aligned with Power BI best practices and dataset limitations.

7. Report re-binding and validation:

Rebuild or enhance reports using the built-in tools of Power BI. Optimize interactive layouts for usability, performance, and mobile accessibility.

8. Test and validate:

Validate reports, monitor capacity metrics, and delete servers to optimize costs. Conduct functional, performance, and security testing to ensure reports deliver accurate insights.

What to Do After You Migrate from SSAS to Power BI

A successful SSAS to Power BI migration ensures data integrity, performance, and user adoption of Power BI. To utilize Power BI’s advanced capabilities, we need to follow the steps below.

• Monitor and optimize: Implement incremental refresh, aggregations, or hybrid tables for performance gains over SSAS. Update any reset data source credentials and verify scheduled refreshes.
• Security and Governance: Ensure that row-level security (RLS), workspace roles, and data access policies are configured. Improve layouts and follow best practices for usability and optimize dashboards for desktop and mobile users.
• User adoption: Offer training sessions to help users understand the features of Power BI. Maintain documentation to improve adoption and reduce support requests.
• Decommission SSAS: Once the Power BI is stable, start decommissioning SSAS components that are no longer required. 

Why Choose Entrans for Your SSAS to Power BI Migration?

SSAS to Power BI migration provides clear benefits. But it also introduces risks related to data consistency, performance, and security. Choosing the right migration partner, like Entrans, will take all the risks associated with it and give measurable results. 

With our proven expertise in migrations, we provide users with interactive dashboards, self-service analytics, and mobile access with better decision-making across the teams. Entrans provides the structured methodology and post-migration support by following industry best practices.

Learn about how we make a measurable business impact. Book a consultation call.