You are a network administrator for your company. The network contains four Windows Server 2003 computers configured as a four-node server cluster. Each cluster node is the preferred owner of a clustered instance of Microsoft SQL Server 2000， and each cluster node is configured as a possible owner of all other instances of SQL Server. All nodes have identically configured hardware. All four nodes operate at a sustained 70 percent CPU average. You add a server that has identically configured hardware to the cluster as a fifth node. You want each SQL Server instance to continue operating at the same level of performance in the event of a single node failure. What should you do？ （）