Configuring failover with Microsoft Cluster Server
Microsoft SQL Server provides Microsoft Cluster Server (MSCS), an advanced database replication technology. The failover functionality provided by the driver does not require this technology, but can work with MSCS to provide comprehensive failover protection. If using failover with MSCS, which determines the alternate server for failover instead of the driver, any alternate server specified must be the same as the primary server. For example:
In addition, alternate servers must mirror data on the primary server or be part of a configuration where multiple database nodes share the same physical data.