In the Active Roles replication model, a replication group includes the Publisher and may include several Subscribers. The Publisher plays a special role in the replication group: it synchronizes data changes between Subscribers. In some scenarios, you might want to move the Publisher role to another SQL Server.
For example, you might need to move the Publisher role to a different SQL Server if the service level becomes insufficient. Because the Publisher receives and synchronizes data changes from all Subscribers, the volume of requests being serviced by the Publisher increases as the number of Subscribers grows. The increased volume of requests respectively increases the workload for SQL Server that holds the Publisher role so its performance can suffer. To resolve this problem, you can transfer the Publisher role to another, more powerful server.
This section provides instructions on how to reconfigure the existing replication group so that the Publisher role is assigned to SQL Server other than the current Publisher. You can perform this task using the Active Roles Console connected to the Administration Service which has a database server currently holding the Publisher role (Publisher Administration Service).
NOTE: The Publisher Administration Service must be up and running. If the Publisher is unavailable, you can assign the Publisher role to a different SQL Server. For more information, see Promoting an SQL Server to Publisher.
To connect to the Publisher Administration Service via the Active Roles Console
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Look for the Active Roles Console application, and then click to start that application.
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Right-click the Console tree root, click Connect, and then select the Administration Service whose database server currently holds the Publisher role.
Use the Active Roles Console to remove all Subscribers and to demote the Publisher as follows.
To remove all Subscribers and demote the Publisher
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In the Console tree, expand Configuration > Server Configuration, and select Configuration Databases.
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In the Details pane, right-click a Subscriber, and click Delete.
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In the confirmation message box, click Yes.
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Repeat the deletion steps for each Subscriber.
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In the details pane, right-click the Publisher, and click Demote.
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In the confirmation message box, click Yes.
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Wait while Active Roles demotes the Publisher.
After demoting the previous Publisher, you can promote the appropriate SQL Server to Publisher and designate the other SQL Servers as Subscribers to the new Publisher, thus configuring the new replication group.
TIP: After you add a Subscriber, the configuration data stored on the Publisher is replicated to the Subscriber, overriding the data on that Subscriber. Therefore, in order to retain your existing Active Roles configuration, it is advisable to assign the Publisher role to SQL Server that belonged to the old replication group. This ensures that each Administration Service in the new replication group inherits the configuration that was in place when you removed the Subscribers and demoted the Publisher.
To configure the new replication group using the Active Roles Console
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Right-click the Console tree root, click Connect, and then select the Administration Service the SQL Server of which you want to hold the Publisher role.
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In the Console tree, expand Configuration > Server Configuration, and select Configuration Databases.
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In the Details pane, right-click the database and click Promote.
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In the confirmation message box, click Yes.
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Wait while Active Roles performs the operation.
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In the Details pane, right-click the Publisher, and click Add Replication Partner.
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On the Welcome page in the New Replication Partner wizard, click Next.
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On the Database Selection page, click Browse.
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To configure the SQL Server of an Administration Service as a Subscriber to this Publisher, specify the corresponding Administration Service in the Connect to Administration Service dialog. Click OK.
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In the New Replication Partner wizard, click Next, click Next, and then click Finish.
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Repeat the steps for adding a replication partner for each SQL Server you want to make a Subscriber.
Once the Publisher becomes unavailable, Subscribers cannot synchronize configuration data. The only way that replication can be recovered is by restoring the current Publisher or making another SQL Server the Publisher.
If the current Publisher cannot be restored, you need to transfer the Publisher role to SQL Server that holds the Subscriber role, and reconfigure the other Subscribers to use the new Publisher. This requires that you first remove all Subscribers from the replication group.