ORA-16808: primary database is not open
Cause: A prior attempt to open the primary database was disallowed because the primary had shut itself down earlier after being isolated from both the fast-start failover observer and the target standby database for more than FastStartFailoverThreshold seconds. It was assumed that a fast-start failover was underway. Since that time, re-contact with either the observer or the target standby database indicates that no such failover had actually occurred. The primary database can now be opened.
Action: Open the database by issuing the SQL*Plus ALTER DATABASE OPEN command.
ORA-16808错误提示主要数据库没有打开。
ORA-16808表示无法更改归档模式，因为主数据库未打开。
当你试图在节点1上执行下面的语句（假设节点2上的数据库已经打开）：
SQL> alter database open read write;
你可能会得到以下错误：
ORA-16808：主数据库未打开
1.确保节点1上的数据库已经打开。
2.使用以下语句打开节点2上的RAC数据库：
SQL> alter database open read write;
3.确认节点2上的数据库已经打开：
SQL> select status from v$instance;