工作目标：主备switchover切换，并将新主库IP更换成旧主库IP，旧主库不再使用.
环境介绍：
主库(rhel 6.5 + 实例名(orcl) + IP 192.168.133.120 + 主机名hisdb)
备库(AnolisOS 7.9 + 实例名(orcldg) + IP 192.168.133.125 + 主机名 hisdbdg)
1、Switchover切换
1.1、主切备
SQL> show parameter db_uni

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
db_unique_name                       string      orcl
SQL> select name,log_mode,open_mode,database_role,switchover_status,db_unique_name from v$database

NAME      LOG_MODE     OPEN_MODE            DATABASE_ROLE    SWITCHOVER_STATUS    DB_UNIQUE_NAME
--------- ------------ -------------------- ---------------- -------------------- ------------------------------
ORCL      ARCHIVELOG   READ WRITE           PRIMARY          SESSIONS ACTIVE      orcl

SQL> alter database commit to switchover to physical standby with session shutdown;

Database altered.
SQL> shutdown immediate
ORA-01012: not logged on
SQL> shutdown abort
ORACLE instance shut down.
SQL> startup mount
ORACLE instance started.

Total System Global Area 2.5388E+10 bytes
Fixed Size                  2265056 bytes
Variable Size            3892314144 bytes
Database Buffers         2.1475E+10 bytes
Redo Buffers               18096128 bytes
Database mounted.
SQL> select name, LOG_MODE, OPEN_MODE, database_role, SWITCHOVER_STATUS, db_unique_name from v$database;

NAME      LOG_MODE     OPEN_MODE            DATABASE_ROLE    SWITCHOVER_STATUS    DB_UNIQUE_NAME
---------      ------------        --------------------           ----------------          --------------------           ------------------------------
ORCL      ARCHIVELOG   MOUNTED              PHYSICAL STANDBY   RECOVERY NEEDED      orcl

1.2、备切主
SQL> select name, LOG_MODE, OPEN_MODE, database_role, SWITCHOVER_STATUS, db_unique_name from v$database

NAME      LOG_MODE     OPEN_MODE            DATABASE_ROLE    SWITCHOVER_STATUS    DB_UNIQUE_NAME
--------- ------------ -------------------- ---------------- -------------------- ------------------------------
ORCL      ARCHIVELOG   READ ONLY WITH APPLY PHYSICAL STANDBY TO PRIMARY           orcldg

SQL> alter database commit to switchover to primary with session shutdown;

Database altered.

SQL> alter database open;

Database altered.

SQL> select name, LOG_MODE, OPEN_MODE, database_role, SWITCHOVER_STATUS, db_unique_name from v$database;

NAME      LOG_MODE     OPEN_MODE            DATABASE_ROLE    SWITCHOVER_STATUS    DB_UNIQUE_NAME
--------- ------------ -------------------- ---------------- -------------------- ------------------------------
ORCL      ARCHIVELOG   READ WRITE           PRIMARY          RESOLVABLE GAP       orcldg

2、IP修改
切换后关闭新备库(orcl)服务器，接下来将新主库服务器IP由192.168.133.125更换为192.168.133.120。
2.1、关实例及监听
SQL> shutdown immediate
[oracle@ hisdbdg ~]$ lsnrctl stop
2.2、修改hosts
[root@ hisdbdg ~]# cat /etc/hosts
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
#192.168.133.125 hisdbdg
192.168.133.120 hisdbdg

说明：将原IP 192.168.133.125注释掉，并将192.168.133.120对应的主机名由hisdb修改为hisdbdg.
[root@ hisdbdg ~]# cat /etc/sysconfig/network
# Created by anaconda
2.3、修改ens32
[root@ hisdbdg ~]# cat /etc/sysconfig/network-scripts/ifcfg-ens32
TYPE=Ethernet
PROXY_METHOD=none
BROWSER_ONLY=no
BOOTPROTO=none
DEFROUTE=yes
IPV4_FAILURE_FATAL=no
IPV6INIT=yes
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
IPV6_ADDR_GEN_MODE=stable-privacy
NAME=ens32
UUID=6afa8502-f6d9-4541-b973-95f201e87075
DEVICE=ens32
ONBOOT=yes
IPADDR=192.168.133.120
PREFIX=24
GATEWAY=192.168.10.254
说明：将IPADDR=192.168.133.125修改为IPADDR=192.168.133.120
2.4、重启network
[root@hisdbdg network-scripts]# service network restart
Restarting network (via systemctl):  
若不行，使用下面指令.
[root@ hisdbdg ~]# systemctl restart network
注意：重启network后SecureCRT需要使用IP 192.168.133.120重新连接新主库.
2.5、修改监听
[oracle@hisdbdg admin]$ cat listener.ora 
# listener.ora Network Configuration File: /home/oracle/app/oracle/product/11.2.0/db_1/network/admin/listener.ora
# Generated by Oracle configuration tools.

SID_LIST_LISTENER =
  (SID_LIST =
    (SID_DESC =
      (GLOBAL_DBNAME = orcl)
      (ORACLE_HOME = /home/oracle/app/oracle/product/11.2.0/db_1)
      (SID_NAME = orcl)
    )
  )

LISTENER =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.133.120)(PORT = 1521))
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))
    )
  )

ADR_BASE_LISTENER = /home/oracle/app/oracle
说明：将HOST = 192.168.133.125修改为HOST = 192.168.133.120, GLOBAL_DBNAME = orcldg修改为GLOBAL_DBNAME = orcl，SID_NAME = orcldg修改为SID_NAME = orcl，如此修改保证客户端此前连接串不用做修改便可连接数据库. SID_NAME的修改做过测试，将db_unique_name修改为orcl就可以.
2.6、修改TNS
[oracle@hisdbdg admin]$ cat tnsnames.ora 
# tnsnames.ora Network Configuration File: /home/oracle/app/oracle/product/11.2.0/db_1/network/admin/tnsnames.ora
# Generated by Oracle configuration tools.

#ORCL =
#  (DESCRIPTION =
#    (ADDRESS = (PROTOCOL = TCP)(HOST = hisdb)(PORT = 1521))
#    (CONNECT_DATA =
#      (SERVER = DEDICATED)
#      (SERVICE_NAME = orcl)
#    )
#  )

ORCL =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.133.120)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = orcl)
    )
  )
说明：将HOST = 192.168.133.125修改为HOST = 192.168.133.120，将SERVICE_NAME =orcldg修改为SERVICE_NAME =orcl，连接服务名由ORCLDG修改为ORCL.如此修改保证此前连接串不用做修改便可连接数据库.
2.7、修改db_unique_name
a、spfile生成pfile，然后将*.db_unique_name='orcldg'修改为*.db_unique_name='orcl'
b、用修改后的pfile生成spfile，关库促使下次启动数据库自动使用spfile.(说明：生成spfile前，对spfile做个备份)
2.8、重启服务
[oracle@hisdbdg admin]$ lsnrctl start
[oracle@hisdbdg admin]$ sqlplus / as sysdba
SQL> startup
2.9、验证监听
[oracle@hisdbdg ~]$ lsnrctl status

LSNRCTL for Linux: Version 11.2.0.4.0 - Production on 24-AUG-2022 09:26:42

Copyright (c) 1991, 2013, Oracle.  All rights reserved.

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=192.168.133.120)(PORT=1521)))
STATUS of the LISTENER
------------------------
Alias                     LISTENER
Version                   TNSLSNR for Linux: Version 11.2.0.4.0 - Production
Start Date                23-AUG-2022 20:28:52
Uptime                    0 days 12 hr. 57 min. 49 sec
Trace Level               off
Security                  ON: Local OS Authentication
SNMP                      OFF
Listener Parameter File   /home/oracle/app/oracle/product/11.2.0/db_1/network/admin/listener.ora
Listener Log File         /home/oracle/app/oracle/diag/tnslsnr/hisdbdg/listener/alert/log.xml
Listening Endpoints Summary...
  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=192.168.133.120)(PORT=1521)))
  (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC1521)))
Services Summary...
Service "orcl" has 2 instance(s).
  Instance "orcl", status UNKNOWN, has 1 handler(s) for this service...
  Instance "orcldg", status READY, has 1 handler(s) for this service...
Service "orclXDB" has 1 instance(s).
  Instance "orcldg", status READY, has 1 handler(s) for this service...
The command completed successfully
说明：pl sql测试正常连接.
3、报错处理
主备切换后，执行以下语句消除主库报警.
SQL> alter system set log_archive_config='' scope=both;
SQL> alter system set log_archive_dest_2='' scope=both;
SQL> alter system set fal_server='' scope=both;
SQL> alter system set fal_client='' scope=both;
SQL> alter system set log_archive_dest_1=’location=/home/oracle/app/oracle/archivelog’ scope=both;