ORA-16659: failover operation in progress
Cause: A primary database that restarted contacted a standby database that is being failed over to.
Action: Shut down the primary database and wait for failover to complete on the standby database. Once failover is complete, restart the old primary database. If the failover occurred due to fast-start failover, restarting the primary database after failover is complete allows it to be automatically reinstated as a standby database to the new primary database.
ORA-16659错误表明一个故障转移操作正在进行当中。
ORA-16659被用在一个高可用性故障转移（多实例）环境当中的时候，如果上一次故障转移操作还没有完全完成时，系统会阻止其他操作。
从一个地方进行备份，然后将它恢复到另一台服务器，以防止灾难发生时的故障转移，可能会产生ORA-16659错误消息。
1.检查它是否正在做一个故障转移操作（比如负载平衡或另一种故障转移操作）
2.检查当前正在执行的故障转移操作的目标节点
3.如果需要，等待故障转移操作完成
4.检查源节点和目标节点是否就绪，并尝试再次执行该操作