Hi,
You've raised a complex and important set of questions around securing Dynamics 365 Finance & Operations data exported via Synapse Link to a Data Lake. Here's a structured response addressing each point:
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### **1. Securing Data Exported via Synapse Link**
When using **Azure Synapse Link for Dataverse** to export F&O data to a Data Lake, the data is stored in **Parquet Delta format**, which supports efficient querying and incremental updates [1](https://learn.microsoft.com/en-us/power-apps/maker/data-platform/azure-synapse-link-select-fno-data). To lock down access:
- Use **Azure RBAC** and **ACLs** to restrict access at the storage level [2](https://learn.microsoft.com/en-us/azure/storage/blobs/data-lake-storage-access-control-model).
- Avoid assigning broad roles like `Storage Blob Data Reader` to users unless absolutely necessary.
- Prefer **Microsoft Entra security groups** for managing access to folders and files.
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### **2. Segregating Data Access by User Groups**
To ensure that only specific users see sensitive data:
- Implement **Row-Level Security (RLS)** and **Column-Level Security (CLS)** in Synapse Dedicated SQL Pools [3](https://techcommunity.microsoft.com/blog/educatordeveloperblog/ways-to-control-who-can-access-data-in-azure-synapse-dw/4290877).
- Use **custom views** in Serverless SQL Pools to mask or exclude sensitive columns.
- Assign **UNMASK** permissions only to privileged roles if using Dedicated SQL Pools.
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### **3. Power BI Model Security**
Power BI supports multiple layers of security [4](https://community.fabric.microsoft.com/t5/Desktop/Safeguarding-Sensitive-Data-Exploring-Power-BI-s-Security/td-p/3724467):
- Use **RLS** to restrict data visibility based on user roles.
- Avoid exposing sensitive columns in the model if data scientists don’t need them.
- Consider **creating separate datasets** for modeling and reporting, with masked or filtered views for data scientists.
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### **4. Locking Down Data Lake for Operational Access Only**
To prevent backend access:
- Use **ACLs** to restrict access to specific folders and files [2](https://learn.microsoft.com/en-us/azure/storage/blobs/data-lake-storage-access-control-model).
- Disable **Shared Key** and **SAS token** access; enforce **Microsoft Entra ID authentication**.
- Use **Private Endpoints** and **Firewall Rules** to limit network-level access.
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### **5. Disaster Recovery for Synapse**
Azure Synapse supports **zone redundancy** and **geo-redundant storage (GZRS)**[5](https://learn.microsoft.com/en-us/azure/architecture/example-scenario/analytics/pipelines-disaster-recovery):
- Use **CI/CD pipelines** with Git integration to replicate Synapse artifacts to a secondary region.
- Consider **user-managed recovery** strategies for Dedicated SQL Pools and Spark Pools.
- Document **RTO/RPO objectives** and perform regular DR drills.
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### **6. Accessing Dataverse Lake via New SQL Pool**
Yes, you can query Dataverse-exported lake data using **Serverless SQL Pools**[6](https://learn.microsoft.com/en-us/azure/synapse-analytics/metadata/database):
- Lake databases created via Spark or Synapse Link are automatically available in Serverless SQL Pools.
- You can define **custom views and procedures** on top of these lake tables.
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### **7. Cost Optimization for Synapse**
Key strategies include[7](https://learn.microsoft.com/en-us/azure/synapse-analytics/plan-manage-costs):
- Use **Serverless SQL Pools** for ad-hoc queries (charged per TB scanned).
- **Pause Dedicated SQL Pools** during off-hours.
- Enable **auto-pause** and **autoscale** for Spark Pools.
- Monitor usage via **Azure Cost Management** and set **budgets and alerts**.
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### **8. Dynamic Data Masking Limitations**
Dynamic Data Masking (DDM) is **not supported** in Serverless SQL Pools[8](https://learn.microsoft.com/en-us/answers/questions/2120635/dynamic-data-masking-on-synapse-serverless-sql-dat). Alternatives:
- Use **custom views** to mask data.
- Combine with **RLS** to restrict access based on user roles.
- For full DDM support, consider using **Dedicated SQL Pools**.
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Please verify if this guidance helps address your architecture and security concerns.
Thanks and best regards,
Daniele
*Note: This response was prepared with support from Copilot to ensure clarity and completeness.*