SQL database mirroring is a method of replicating the databases on one SQL server to another. Database mirroring can reduce or prevent down time in the event of a failure on the primary SQL server.

The Enterprise Vault server is connected to the primary SQL server, and the contents of Enterprise Vault SQL databases are replicated in real time to another SQL server.

In the event of a failure on the primary SQL server, Enterprise Vault can be configured to immediately begin using the secondary server. This is accomplished by temporarily adding or adjusting the DNS host or alias entry for the primary SQL server to route traffic to the secondary server, or by editing to the hosts file on the Enterprise Vault server.

In order to redirect Enterprise Vault SQL traffic to a secondary mirror, follow these steps:

1. Stop the Enterprise Vault services.
    
2. Failover all of the SQL databases to the secondary SQL server mirror.
    
3. Based on the network configuration, follow one of these steps:
    
   1. On the DNS server, adjust the host or alias entry for the primary SQL server to reflect the secondary server's IP address
        
   2. On the Enterprise Vault server, adjust the hosts file (usually C:\Windows\System32\Drivers\etc\hosts) to associate the IP address of the secondary SQL server with the hostname of the primary SQL server
        
4. Start the Enterprise Vault services.
    

The Enterprise Vault services will start normally. When the primary server is repaired, repeat the process to switch Enterprise Vault back to the primary server.

Note: SQL Server database mirroring is not a SQL Server cluster configuration. For information on SQL clusters, please consult Microsoft SQL server documentation.