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Limitations in Microsoft Fabric mirrored databases from Azure SQL Managed Instance (Preview)

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Current limitations in the Microsoft Fabric mirrored databases from Azure SQL Managed Instance are listed in this page. This page is subject to change.

For troubleshooting, see:

Feature availability

You can configure Azure SQL Managed Instance for mirroring if it is deployed to any Azure region, except for these regions currently: East US 2; West US 2; Central US; West US.

The feature availability also depends on Fabric regions. For a complete list of Fabric region support, see Fabric regions that support Mirroring.

Database level limitations

  • Mirroring on Azure SQL Managed Instance is only available for instances that have their Update Policy set to Always up to date. SQL Server 2022 version of SQL Managed Instance doesn't support mirroring.
  • Geo Disaster Recovery setup isn't supported by Mirroring.
  • Fabric Mirroring for Azure SQL Managed Instance is only supported on a writable primary database.
  • An Azure SQL Managed Instance database can't be mirrored if the database has: enabled Change Data Capture (CDC), Transactional Replication, or the database is already mirrored in another Fabric workspace.
  • The maximum number of tables that can be mirrored into Fabric is 500 tables. Any tables above the 500 limit currently can't be replicated.
    • If you select Mirror all data when configuring Mirroring, the tables to be mirrored over are the first 500 tables when all tables are sorted alphabetically based on the schema name and then the table name. The remaining set of tables at the bottom of the alphabetical list aren't mirrored over.
    • If you unselect Mirror all data and select individual tables, you are prevented from selecting more than 500 tables.
  • The database copy/move feature isn't supported on databases that are mirrored. If you move or copy a database with mirroring enabled, the copy will report a mirroring error state.
  • If your SQL managed instance database is set up to use Azure SQL Managed Instance Link feature, the readable replica isn't supported to be a source for Fabric mirroring.
  • If your database is configured for mirroring and then renamed, the Monitor Mirroring functionality will stop working. Renaming the database to the name it had when mirroring was set up will resolve the issue.

Permissions in the source database

  • Row-level security is supported, but permissions are currently not propagated to the replicated data in Fabric OneLake.
  • Object-level permissions, for example granting permissions to certain columns, aren't currently propagated to the replicated data in Fabric OneLake.
  • Dynamic data masking settings aren't currently propagated from the source database into Fabric OneLake.
  • To successfully configure Mirroring for Azure SQL Managed Instance, the principal used to connect to the source SQL managed instance needs to be granted CONTROL or db_owner permissions. It's recommended to only grant this only on the database being mirrored - do not do it on the entire server level.

Network and connectivity security

  • The source SQL managed instance needs to enable public endpoint and allow Azure services to connect to it.
  • The System Assigned Managed Identity (SAMI) of the Azure SQL Managed Instance needs to be enabled and must be the primary identity.
  • The Azure SQL Managed Instance service principal name (SPN) contributor permissions shouldn't be removed from the Fabric mirrored database item.
  • User Assigned Managed Identity (UAMI) isn't supported.
  • Mirroring across Microsoft Entra tenants isn't supported where an Azure SQL Managed Instance and the Fabric workspace are in separate tenants. 
  • Microsoft Purview Information Protection/sensitivity labels defined in Azure SQL Managed Instance aren't mirrored to Fabric OneLake.

Table level

  • A table that doesn't have a defined primary key can't be mirrored.
    • A table using a primary key defined as nonclustered primary key can't be mirrored.
    • A table can't be mirrored if the primary key is one of the data types: sql_variant, timestamp/rowversion
    • A table cannot be mirrored if the primary key is one of these data types: datetime2(7), datetimeoffset(7), time(7), where 7 is seven digits of precision.
    • Delta lake supports only six digits of precision.
      • Columns of SQL type datetime2, with precision of 7 fractional second digits, do not have a corresponding data type with same precision in Delta files in Fabric OneLake. A precision loss happens if columns of this type are mirrored and seventh decimal second digit will be trimmed.
      • The datetimeoffset(7) data type does not have a corresponding data type with same precision in Delta files in Fabric OneLake. A precision loss (loss of time zone and seventh time decimal) occurs if columns of this type are mirrored.
    • Clustered columnstore indexes aren't currently supported.
  • If one or more columns in the table is of type Large Binary Object (LOB) with a size > 1 MB, the column data is truncated to size of 1 MB in Fabric OneLake. Configure the max text repl size server configuration option to allow more than 65,536 bytes if you want to allow large inserts.
  • Source tables that have any of the following features in use can't be mirrored:
    • Temporal history tables and ledger history tables 
    • Always Encrypted
    • In-memory tables
    • Graph 
    • External tables 
  • The following table-level data definition language (DDL) operations aren't allowed on source tables when enabled for SQL Managed Instance mirroring to Microsoft Fabric.
    • Switch/Split/Merge partition
    • Alter primary key 
    • Truncate table
  • When there's DDL change, a complete data snapshot is restarted for the changed table, and entire table data is reseeded into Fabric OneLake.
  • Currently, a table cannot be mirrored if it has the json data type.
    • Currently, you cannot ALTER a column to the json data type when a table is mirrored.
  • Views and Materialized views aren't supported for mirroring.

Column level

  • If the source table contains computed columns, these columns can't be mirrored to Fabric OneLake. 
  • If the source table contains columns with one of these data types, these columns can't be mirrored to Fabric OneLake. The following data types are unsupported for mirroring:
    • image
    • text/ntext
    • xml
    • json
    • rowversion/timestamp
    • sql_variant
    • User Defined Types (UDT)
    • geometry
    • geography
  • Column names for a SQL table can't contain spaces nor the following characters: , ; { } ( ) \n \t =.
  • The following column level data definition language (DDL) operations aren't supported on source tables when they're enabled for SQL Managed Instance mirroring to Microsoft Fabric:
    • Alter column
    • Rename column (sp_rename)

Mirrored item limitations

  • User needs to be a member of the Admin/Member role for the workspace to create SQL Managed Instance mirroring. 
  • Stopping mirroring disables mirroring completely. 
  • Starting mirroring reseeds all the tables, effectively starting from scratch. 
  • If Fabric capacity is stopped and then restarted, mirroring will stop working and needs to be manually restarted. There won't be warnings/error messages indicating that mirroring stopped working.

SQL analytics endpoint limitations

Supported regions

The following are the Fabric regions that support mirroring:

Asia Pacific:

  • Australia East
  • Australia Southeast
  • Central India
  • East Asia
  • Japan East
  • Korea Central
  • Southeast Asia
  • South India

Europe

  • North Europe
  • West Europe
  • France Central
  • Germany West Central
  • Norway East
  • Sweden Central
  • Switzerland North
  • Switzerland West
  • UK South
  • UK West

Americas:

  • Brazil South
  • Canada Central
  • Canada East
  • East US
  • East US2
  • North Central US
  • South Central US
  • West US
  • West US2

Middle East and Africa:

  • South Africa North
  • UAE North

Next step

Tutorial: Configure Microsoft Fabric mirrored databases from Azure SQL Managed Instance (Preview)

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