按照网上的教程，修改了sqlnet.ora

NAMES.DIRECTORY_PATH= (TNSNAMES, ONAMES, HOSTNAME)

SQLNET.ALLOWED_LOGON_VERSION_SERVER=11;

SQLNET.ALLOWED_LOGON_VERSION_SERVER=12;

SQLNET.ALLOWED_LOGON_VERSION_CLIENT=11;

SQLNET.ALLOWED_LOGON_VERSION_CLIENT=12;

就是因为这个配置，然后就出现Ora-12514了。

startup的时候提示：

ORA-01012: not logged on

查看监听状态会提示：

instance status blocked

需要按照地址：https://www.cnblogs.com/ios9/p/8078977.html 教程关掉oracle

[oracle@localhost ~]$ kill oracle

 23 -bash: kill: oracle: arguments must be process or job IDs

 24 [oracle@localhost ~]$ ps -ef|grep ora_dbw0_$ORACLE_SID

 25 oracle    4619     1  0 Dec20 ?        00:00:37 ora_dbw0_orcl

 26 oracle   11382 10996  0 09:47 pts/3    00:00:00 grep ora_dbw0_orcl

 27 [oracle@localhost ~]$ kill -9 4619

 28 [oracle@localhost ~]$ kill 10996

 29 [oracle@localhost ~]$ ps -ef|grep ora_dbw0_$ORACLE_SID

 30 oracle   11386 10996  0 09:47 pts/3    00:00:00 grep ora_dbw0_orcl

启动还是不行，最后把sqlnet.ora该回去，注释掉部分不要的，正确配置如下：

# sqlnet.ora Network Configuration File: /opt/oracle/product/18c/dbhome_1/network/admin/sqlnet.ora

# Generated by Oracle configuration tools.



NAMES.DIRECTORY_PATH= (TNSNAMES, ONAMES, HOSTNAME)

#SQLNET.ALLOWED_LOGON_VERSION_SERVER=11;

#SQLNET.ALLOWED_LOGON_VERSION_SERVER=12;

#SQLNET.ALLOWED_LOGON_VERSION_SERVER=18;

SQLNET.ALLOWED_LOGON_VERSION_CLIENT=11;

SQLNET.ALLOWED_LOGON_VERSION_CLIENT=12;

SQLNET.ALLOWED_LOGON_VERSION_CLIENT=18;

startup数据库，终于起来了。再重启监听就好了。