Microsoft KB Archive/941526

= The Failover Partner connection string attribute cannot connect to a mirror partner server by using the SQL Native Client OLE DB provider and the SQL Native Client ODBC driver in a .NET Framework-based application =

Article ID: 941526

Article Last Modified on 12/3/2007

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APPLIES TO


 * Microsoft .NET Framework 2.0

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SYMPTOMS
In a Microsoft .NET Framework-based application, the Failover Partner connection string attribute cannot connect to a mirror partner server by using the SQL Native Client OLE DB provider and the SQL Native Client ODBC driver.

Consider the following scenario:
 * You have a Microsoft .NET Framework-based application that enables fast database mirroring between two servers that are running Microsoft SQL Server 2005.
 * The mirror partner is a named instance of SQL Server. This named instance contains an alias in the SQL Server 2005 Configuration Manager client tool.
 * The mirror partner server is connected to a nondefault port.
 * The connectivity to the principal server is lost. Then, the application tries to connect to a mirror partner server.
 * The.NET Framework-based application specifies an alias of the mirror partner server instead of the full server name and port number.

In this scenario, the SQL Native Client OLE DB provider and the SQL Native Client ODBC driver cannot connect to the mirror partner server. Additionally, you receive the following error message:

login timeout



CAUSE
This problem occurs because the SQL Native Client OLE DB provider and the SQL Native Client ODBC driver do not correctly translate the alias to an IP address before the .NET Framework-based application tries to connect to the mirror partner server.



WORKAROUND
To work around this problem, use one of the following methods.
 * Specify the full server name and the port number in the Failover Partner attribute.
 * Enable the mirror partner server to run while it is connected on the default port. The default port number is 1433.
 * Enable User Datagram Protocol (UDP) traffic to the mirror partner server over port number 1434.



MORE INFORMATION
For more information about database mirroring, visit the following Microsoft Developer Network (MSDN) Web site:

http://msdn2.microsoft.com/en-us/library/ms366348.aspx

The product documentation does not indicate how to use an alias name in the Failover Partner connection string attribute.

You can specify the mirror partner server by using the Failover Partner attribute. The simplest way to determine the server instance is by its system name. For example, you can use the following format:

[\ ]

Or, you can use the IP address and the port number in the Failover Partner attribute.

Keywords: kbtshoot kbfix kbprb KB941526

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