Known SQL Data Sync Limits

Known SQL Data Sync Limits

Updated: August 28, 2015


SQL Azure Data Sync Icon

Welcome to SQL Data Sync (Preview). This topic is the second of five topics you should be familiar with before you design and implement a data synchronization plan. The five preparatory topics are:

The Microsoft Azure SQL Data Sync plug-in on the Microsoft Azure Silverlight portal has been decommissioned. Going forward, use the Microsoft Azure Management portal, for Azure SQL Data Sync.

You access SQL Data Sync (Preview) via the SYNC tab under SQL Database at the Microsoft Azure Management portal. The SYNC tab is only available when you have one or more sync groups. See the topic How To: Create a Sync Group (SDS) for guidance on creating and modifying a sync group from this portal.

See the Navigation section below for links to topics you should read before you start and guidance on creating and modifying sync groups.

A: SQL Data Sync (Preview) Preview has the following limits per SQL Data Sync (Preview) Server:


Instance Maximum

Maximum number of sync groups any database can belong to.


Maximum number of endpoints in a single sync group


There may be up to 30 endpoints in a single sync group if there is only one sync group. If there is more than one sync group the total number of endpoints across all sync groups cannot exceed 30.

If a database belongs to multiple sync groups it is counted as multiple endpoints, not one.

Maximum number of on-premises endpoints in a single sync group.


Filters per table

Due to SQL Server constraints and SQL Data Sync (Preview) overhead the number of column filters is limited.

  • Up to 12 column filters per table.

  • An optional 13th column filter if it is on the primary key column.

The SQL Data Sync (Preview) Preview UI permits any number of columns filters. Exceeding the above limits results in a provisioning failure when you deploy the sync group.

Characters that cannot be used in object names

The names of objects (databases, tables, columns) cannot contain the printable characters period (.), left square bracket ([) or right square bracket (]).


Dimension Limit

Database, table, schema, and column names

50 character per name

Tables in a sync group


Columns in a table in a sync group


Data row size on a table


SQL Data Sync (Preview) doesn’t support synchronizing tables with same name in different schemas.

SQL Data Sync (Preview) is a feature of SQL Database. From the Azure Management portal you can perform all tasks necessary to create, deploy, and modify a sync group.


How to create a sync group

There are six steps to creating a sync group from the Azure Management portal. Details on each step can be found by following these links.

  1. Sign in to the Azure SQL Database Management portal
    SQL Data Sync (Preview) is found as a tab under SQL Database only after you create a sync group.

  2. Install a SQL Data Sync Client Agent

  3. Register a SQL Server database with a Client Agent

  4. Create your sync group

  5. Define your data sync

  6. Configure your sync group (SDS)

How to modify a sync group

You can modify a sync group’s schema by adding/removing tables or columns in the sync group; or by altering a column’s width or data type. Details can be found by following the links.

See Also

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