博望坡

 Oracle 10g rac 始支持两个instance的failover和loadbalance。示例如下：

VMRACTEST.HF.COM=
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = TCP) (HOST = 172.16.209.47) (PORT = 1521))
      (ADDRESS = (PROTOCOL = TCP) (HOST = 172.16.209.49) (PORT = 1521))
        (LOAD_BALANCE = yes)
        (CONNECT_DATA =
            (SERVER = DEDICATED)
            (SERVICE_NAME = vmractest.hf.com)
        (FAILOVER_MODE =
            (TYPE = SELECT)
            (METHOD = BASIC)
            (RETRIES = 180)
            (DELAY = 5))
        )
    )

 如上配置，若使用oci client连接RAC则client将连接到172.16.209.47 或 172.16.209.49的任意一台实例上，假设我们连到了49上。TCP Connection状态为ESTABLISHED。当49的instance发生故障，该client端TCP连接状态变为Close_WAIT，不要以为连接已断。当我们执行数据库操作时，oci将重连到47的TCP Connection