Configuring the database connection to use the listener
To enable the use of the availability group listener, you need to modify the database connection setting of the Administration Service. You can specify the availability group listener in the SQL Server field on the Change Active Roles Database wizard pages provided by Active Roles Configuration Center.
Depending upon the location of the Management History database in your Active Roles environment, you need to specify the listener in the SQL Server field on the Connection to Database page, on the Connection to Management History Database page, or on both pages. The value in the SQL Server field must identify the DNS host name and, optionally, the TCP port of the listener of the availability group to which the database belongs. For example, if the DNS host name of the listener is AGListener and the TCP port used by this listener is 1234
, the value is AGListener,1234. You may omit the port number in case of the default port, 1433.
Management History data stored in a separate database
Using Active Roles, it is mandatory to store the Management History data in a separate database. If you do this, then you have two databases, the Configuration database and the Management History database, each of which (or both) can belong an availability group. In this case:
- If the Configuration database belongs to an availability group, specify the listener of that availability group in the SQL Server field on the Connection to Database page in the Change Active Roles Database wizard. Otherwise, leave the value data intact.
- If the Management History database belongs to an availability group, specify the listener of that availability group in the SQL Server field on the Connection to Management History Database page in the Change Active Roles Database wizard. Otherwise, leave the value data intact.
To specify the listener
- Start Configuration Center on the computer running the Administration Service, or connect Configuration Center to that computer.
You can start Configuration Center by selecting Active Roles Configuration Center on the Apps page or Start menu, depending upon the version of your Windows operating system. For detailed instructions, see Running Configuration Center.
- On the Dashboard page in the Configuration Settings main window, click Manage Settings in the Administration Service area.
- On the Administration Service page that opens, click Change in the Active Roles databases area.
- On the Connection to Database page in the Change Active Roles Database wizard that appears, do the following:
- If the Configuration database belongs to an availability group, then, in the SQL Server field, supply the DNS host name and, optionally, the TCP port of the listener of that availability group. Otherwise, don’t change the value in the SQL Server field.
- If the Administration Service uses the SQL Server authentication option, type the password of the SQL login used for connection to the Configuration database.
- Click Next.
- On the Management History Database Options page, select the Existing Active Roles database option (if not already selected), and then click Next.
- On the Connection to Management History Database page, do the following:
- If the Management History database belongs to an availability group, then, in the SQL Server field, supply the DNS host name and, optionally, the TCP port of the listener of that availability group. Otherwise, don’t change the value in the SQL Server field.
- If the Administration Service uses the SQL Server authentication option, type the password of the SQL login used for connection to the Management History database.
- Click Next.
- Follow the instructions in the wizard to complete the configuration.
Using database mirroring
Active Roles can use the Microsoft SQL Server database mirroring technology to improve the availability of the Administration Service. Database mirroring provides a standby database server that supports failover. Once the current database server fails, the Administration Service can recover quickly by automatically reconnecting to the standby server.
Database mirroring increases database availability by supporting rapid failover. This technology can be used to maintain two copies of a single Active Roles database on different server instances of SQL Server Database Engine. One server instance serves the database to the Administration Service; this instance is referred to as the principal server. The other instance acts as a standby server; this instance is referred to as the mirror server.
Role switching
Within the context of database mirroring, the mirror server acts as the failover partner for the principal server. In the event of a disaster, the mirror server takes over the role of the principal server, bringing the mirror copy of the database online as the new principal database. The former principal server, if available, then assumes the role of the mirror server. This process, known as role switching, can take the form of:
- Automatic failover If the principal server becomes unavailable, quickly brings the mirror copy of the database online as the new principal database.
- Manual failover Allows the database owner to reverse the roles of the failover partners, if necessary.
- Forced service If the principal server becomes unavailable, allows the database owner to restore access to the database by forcing the mirror server to take over the role of the principal server.
In any role-switching scenario, as soon as the new principal database comes online, the Administration Service can recover by automatically reconnecting to the database.
For more information about the database mirroring technology, and instructions on how to set up and administer database mirroring on SQL Server, see the “Database Mirroring” topics in the SQL Server product documentation at http://msdn.microsoft.com/en-us/library/bb934127.aspx.
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NOTE: The Active Roles replication function is not supported for the databases that have mirroring set up. If you attempt to perform the “Promote to Publisher” or “Add Subscriber” operation on such a database, you receive an error. |