Domain Groups for Clustered Services
Use the Domain Groups for Clustered Services page of the Microsoft SQL Server Installation Wizard to specify domain groups for the clustered services that will be installed as part of your SQL Server 2005 failover cluster.
For each clustered service in the instance of SQL Server that you are installing, enter the domain and group name in the format <DomainName>\<GroupName>, subject to the following guidelines:
The domain and group names must already exist. If necessary, ask your domain administrator for the names of existing domain groups, or to create domain groups for your failover cluster.
The account under which SQL Server Setup is running must have privileges to add accounts to the domain groups.
Each service should use a different domain group.
The SQL Server domain groups should not be shared with any other application.
Note that SQL Server accounts will not be removed from the groups if SQL Server is uninstalled or if the accounts are changed. A domain administrator must ensure that all unwanted accounts are removed following removal of SQL Server.