本文文档结构图：
本篇发布的有些晚，之前的8篇文章见 http://blog.itpub.net/26736162/viewspace-1290405/
1.1 测试DATAGUARDSWITCHOVER功能
1.1.1 RAC主库、ActiveDataguard角色切换
即rac主库切换为物理备库，物理备库切换为rac主库。
1.1.1.1 ①主库修改相关参数fal_client、fal_server：
fal_server 指定为主库即primary的网络服务名
fal_client 指定为备库即standby的网络服务名
通常来说，主库和备库是反过来的，便于主备库的切换。
首先需要确保主库采用spfile启动，然后在其中任何一个节点执行以下命令:
alter system set fal_client='racdb1' sid='racdb1';
alter system set fal_client='racdb2' sid='racdb2';
alter system set fal_server='phydb' sid='*';
SQL> show parameter spfile
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
spfile string +DATA/racdb/spfileracdb.ora
SQL> show parameter fal
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
fal_client string
fal_server string
SQL> alter system set fal_client='racdb1' sid='racdb1';
System altered.
SQL> alter system set fal_client='racdb2' sid='racdb2';
System altered.
SQL> alter system set fal_server='phydb' sid='*';
System altered.
---rac1查看结果：
SQL> show parameter fal
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
fal_client string racdb1
fal_server string phydb
SQL>
---rac2查看结果：
SQL> show parameter fal
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
fal_client string racdb2
fal_server string phydb
SQL>
1.1.1.2 ②主库创建standbylogfile：
创建standby_logfile 之前查看可以得到已经存在4组日志，且无standby_logfile，每个大小为50M
SQL> col member for a60
SQL> select * from v$logfile;
GROUP# STATUS TYPE MEMBER IS_REC
---------- -------------- -------------- ------------------------------------------------------------ ------
2 ONLINE +DATA/racdb/onlinelog/group_2.262.859849495 NO
2 ONLINE +FRA/racdb/onlinelog/group_2.258.859849495 YES
1 ONLINE +DATA/racdb/onlinelog/group_1.261.859849493 NO
1 ONLINE +FRA/racdb/onlinelog/group_1.257.859849493 YES
3 ONLINE +DATA/racdb/onlinelog/group_3.266.859850179 NO
3 ONLINE +FRA/racdb/onlinelog/group_3.259.859850181 YES
4 ONLINE +DATA/racdb/onlinelog/group_4.267.859850183 NO
4 ONLINE +FRA/racdb/onlinelog/group_4.260.859850187 YES
已选择8行。
SQL> select * from v$standby_log;
未选定行
SQL> select group#, bytes/1024/1024 from v$log;
GROUP# BYTES/1024/1024
---------- ---------------
1 50
2 50
3 50
4 50
SQL>
开始创建 standby logfile：
alter database add standby logfile thread 1 group 5 size 50M ,group 6 size 50M ,group 7 size 50M ;
alter database add standby logfile thread 2 group 8 size 50M ,group 9 size 50M ,group 10 size 50M ;
SQL> alter database add standby logfile thread 1 group 5 size 50M ,group 6 size 50M ,group 7 size 50M ;
数据库已更改。
SQL> alter database add standby logfile thread 2 group 8 size 50M ,group 9 size 50M ,group 10 size 50M ;
数据库已更改。
SQL> select * from v$logfile;
GROUP# STATUS TYPE MEMBER IS_REC
---------- -------------- -------------- ------------------------------------------------------------ ------
2 ONLINE +DATA/racdb/onlinelog/group_2.262.859849495 NO
2 ONLINE +FRA/racdb/onlinelog/group_2.258.859849495 YES
1 ONLINE +DATA/racdb/onlinelog/group_1.261.859849493 NO
1 ONLINE +FRA/racdb/onlinelog/group_1.257.859849493 YES
3 ONLINE +DATA/racdb/onlinelog/group_3.266.859850179 NO
3 ONLINE +FRA/racdb/onlinelog/group_3.259.859850181 YES
4 ONLINE +DATA/racdb/onlinelog/group_4.267.859850183 NO
4 ONLINE +FRA/racdb/onlinelog/group_4.260.859850187 YES
5 STANDBY +DATA/racdb/onlinelog/group_5.269.863272613 NO
5 STANDBY +FRA/racdb/onlinelog/group_5.368.863272615 YES
6 STANDBY +DATA/racdb/onlinelog/group_6.270.863272617 NO
6 STANDBY +FRA/racdb/onlinelog/group_6.369.863272619 YES
7 STANDBY +DATA/racdb/onlinelog/group_7.271.863272621 NO
7 STANDBY +FRA/racdb/onlinelog/group_7.372.863272621 YES
8 STANDBY +DATA/racdb/onlinelog/group_8.272.863272637 NO
8 STANDBY +FRA/racdb/onlinelog/group_8.375.863272637 YES
9 STANDBY +DATA/racdb/onlinelog/group_9.273.863272639 NO
9 STANDBY +FRA/racdb/onlinelog/group_9.379.863272641 YES
10 STANDBY +DATA/racdb/onlinelog/group_10.274.863272643 NO
10 STANDBY +FRA/racdb/onlinelog/group_10.381.863272643 YES
已选择20行。
SQL> select * from v$standby_log;
GROUP# DBID THREAD# SEQUENCE# BYTES BLOCKSIZE USED ARCHIV STATUS FIRST_CHANGE# FIRST_TIME NEXT_CHANGE# NEXT_TIME LAST_CHANGE# LAST_TIME
---------- -------------------------------------------------------------------------------- ---------- ---------- ---------- ---------- ---------- ------ -------------------- ------------- -------------- ------------ -------------- ------------ --------------
5 UNASSIGNED 1 0 52428800 512 0 YES UNASSIGNED
6 UNASSIGNED 1 0 52428800 512 0 YES UNASSIGNED
7 UNASSIGNED 1 0 52428800 512 0 YES UNASSIGNED
8 UNASSIGNED 2 0 52428800 512 0 YES UNASSIGNED
9 UNASSIGNED 2 0 52428800 512 0 YES UNASSIGNED
10 UNASSIGNED 2 0 52428800 512 0 YES UNASSIGNED
已选择6行。
SQL>
1.1.1.3 ③主库修改相关参数standby_file_management、db_file_name_convert 、log_filename_convert
修改前：
SQL> show parameter standby_file
NAME TYPE VALUE
------------------------------------ ---------------------- ------------------------------
standby_file_management string MANUAL
SQL> show parameter db_file_name
NAME TYPE VALUE
------------------------------------ ---------------------- ------------------------------
db_file_name_convert string
SQL> show parameter log_file_name
NAME TYPE VALUE
------------------------------------ ---------------------- ------------------------------
log_file_name_convert string
SQL>
修改：
SQL> alter system set db_file_name_convert='+DATA/phydb/','+DATA/racdb/' sid='*' scope=spfile;
系统已更改。
SQL> alter system set log_file_name_convert='+DATA/phydb/','+DATA/racdb/' sid='*' scope=spfile;
系统已更改。
修改后查看：
SELECT * FROM v$spparameter a WHERE a.NAME like '%file_name_convert';
1.1.1.4 ④停止RAC节点2：
主库状态：
SQL> select dbid,name,current_scn,protection_mode,database_role,force_logging,open_mode,switchover_status from gv$database;
DBID NAME CURRENT_SCN PROTECTION_MODE DATABASE_ROLE FOR OPEN_MODE SWITCHOVER_STATUS
---------- --------- ----------- -------------------- ---------------- --- -------------------- --------------------
857466254 RACDB 2809285 MAXIMUM PERFORMANCE PRIMARY YES READ WRITE TO STANDBY
857466254 RACDB 2809285 MAXIMUM PERFORMANCE PRIMARY YES READ WRITE TO STANDBY
SQL>
备库状态：
SQL> select dbid,name,current_scn,protection_mode,database_role,force_logging,open_mode,switchover_status from gv$database;
DBID NAME CURRENT_SCN PROTECTION_MODE DATABASE_ROLE FOR OPEN_MODE SWITCHOVER_STATUS
---------- --------- ----------- -------------------- ---------------- --- -------------------- --------------------
857466254 RACDB 2813423 MAXIMUM PERFORMANCE PHYSICAL STANDBY YES READ ONLY WITH APPLY NOT ALLOWED
SQL>
停掉rac2主库：
SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL>
再次查看rac主库：
SQL> select dbid,name,current_scn,protection_mode,database_role,force_logging,open_mode,switchover_status from gv$database;
DBID NAME CURRENT_SCN PROTECTION_MODE DATABASE_ROLE FOR OPEN_MODE SWITCHOVER_STATUS
---------- --------- ----------- -------------------- ---------------- --- -------------------- --------------------
857466254 RACDB 2814040 MAXIMUM PERFORMANCE PRIMARY YES READ WRITE TO STANDBY
SQL>
1.1.1.5 ⑤RAC 节点 1 切换原 RAC 主库到备库：
rac主库执行：
SQL> show parameter instance_name
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
instance_name string racdb1
SQL> select dbid,name,current_scn,protection_mode,database_role,force_logging,open_mode,switchover_status from gv$database;
DBID NAME CURRENT_SCN PROTECTION_MODE DATABASE_ROLE FOR OPEN_MODE SWITCHOVER_STATUS
---------- --------- ----------- -------------------- ---------------- --- -------------------- --------------------
857466254 RACDB 2814245 MAXIMUM PERFORMANCE PRIMARY YES READ WRITE TO STANDBY
SQL> alter database commit to switchover to physical standby with session shutdown;
Database altered.
SQL> select dbid,name,current_scn,protection_mode,database_role,force_logging,open_mode,switchover_status from gv$database;
DBID NAME CURRENT_SCN PROTECTION_MODE DATABASE_ROLE FOR OPEN_MODE SWITCHOVER_STATUS
---------- --------- ----------- -------------------- ---------------- --- -------------------- --------------------
857466254 RACDB 2814358 MAXIMUM PERFORMANCE PHYSICAL STANDBY YES READ WRITE RECOVERY NEEDED
SQL>
----原物理备库查看：
SQL> select dbid,name,current_scn,protection_mode,database_role,force_logging,open_mode,switchover_status from gv$database;
DBID NAME CURRENT_SCN PROTECTION_MODE DATABASE_ROLE FOR OPEN_MODE SWITCHOVER_STATUS
---------- --------- ----------- -------------------- ---------------- --- -------------------- --------------------
857466254 RACDB 2834309 MAXIMUM PERFORMANCE PHYSICAL STANDBY YES READ ONLY WITH APPLY SESSIONS ACTIVE
SQL>
1.1.1.6 ⑥ 切换原物理备库到主库角色：
原物理备库下执行，注意执行该步骤的时候不能有其它的回话连接到dg库，否则报错：
SQL> alter database commit to switchover to primary;
alter database commit to switchover to primary
*
ERROR at line 1:
ORA-01093: ALTER DATABASE CLOSE only permitted with no sessions connected
SQL> show parameter instance_name
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
instance_name string phydb
SQL> select dbid,name,current_scn,protection_mode,database_role,force_logging,open_mode,switchover_status from gv$database;
DBID NAME CURRENT_SCN PROTECTION_MODE DATABASE_ROLE FOR OPEN_MODE SWITCHOVER_STATUS
---------- --------- ----------- -------------------- ---------------- --- -------------------- --------------------
857466254 RACDB 2834309 MAXIMUM PERFORMANCE PHYSICAL STANDBY YES READ ONLY TO PRIMARY
SQL> alter database commit to switchover to primary;
Database altered.
SQL> select dbid,name,current_scn,protection_mode,database_role,force_logging,open_mode,switchover_status from gv$database;
DBID NAME CURRENT_SCN PROTECTION_MODE DATABASE_ROLE FOR OPEN_MODE SWITCHOVER_STATUS
---------- --------- ----------- -------------------- ---------------- --- -------------------- --------------------
857466254 RACDB 0 MAXIMUM PERFORMANCE PRIMARY YES MOUNTED NOT ALLOWED
SQL> alter database open;
Database altered.
SQL> select dbid,name,current_scn,protection_mode,database_role,force_logging,open_mode,switchover_status from gv$database;
DBID NAME CURRENT_SCN PROTECTION_MODE DATABASE_ROLE FOR OPEN_MODE SWITCHOVER_STATUS
---------- --------- ----------- -------------------- ---------------- --- -------------------- --------------------
857466254 RACDB 2834936 MAXIMUM PERFORMANCE PRIMARY YES READ WRITE FAILED DESTINATION
SQL>
1.1.1.7 ⑦ 将原 RAC 主库 2 个实例都启动到 MOUNT 状态：
[grid@rac1 ~]$ crs_stat -t
Name Type Target State Host
------------------------------------------------------------
ora.DATA.dg ora....up.type ONLINE ONLINE rac1
ora.FRA.dg ora....up.type ONLINE ONLINE rac1
ora....ER.lsnr ora....er.type ONLINE ONLINE rac1
ora....N1.lsnr ora....er.type ONLINE ONLINE rac1
ora.OCR.dg ora....up.type ONLINE ONLINE rac1
ora.asm ora.asm.type ONLINE ONLINE rac1
ora.cvu ora.cvu.type ONLINE ONLINE rac2
ora.gsd ora.gsd.type ONLINE OFFLINE
ora....network ora....rk.type ONLINE ONLINE rac1
ora.oc4j ora.oc4j.type ONLINE ONLINE rac2
ora.ons ora.ons.type ONLINE ONLINE rac1
ora....SM1.asm application ONLINE ONLINE rac1
ora....C1.lsnr application ONLINE ONLINE rac1
ora.rac1.gsd application ONLINE OFFLINE
ora.rac1.ons application ONLINE ONLINE rac1
ora.rac1.vip ora....t1.type ONLINE ONLINE rac1
ora....SM2.asm application ONLINE ONLINE rac2
ora....C2.lsnr application ONLINE ONLINE rac2
ora.rac2.gsd application ONLINE OFFLINE
ora.rac2.ons application ONLINE ONLINE rac2
ora.rac2.vip ora....t1.type ONLINE ONLINE rac2
ora.racdb.db ora....se.type OFFLINE OFFLINE
ora.scan1.vip ora....ip.type ONLINE ONLINE rac1
[grid@rac1 ~]$ srvctl status database -d racdb
Instance racdb1 is not running on node rac1
Instance racdb2 is not running on node rac2
[grid@rac1 ~]$ srvctl start database -d racdb -o mount
[grid@rac1 ~]$ crs_stat -t
Name Type Target State Host
------------------------------------------------------------
ora.DATA.dg ora....up.type ONLINE ONLINE rac1
ora.FRA.dg ora....up.type ONLINE ONLINE rac1
ora....ER.lsnr ora....er.type ONLINE ONLINE rac1
ora....N1.lsnr ora....er.type ONLINE ONLINE rac1
ora.OCR.dg ora....up.type ONLINE ONLINE rac1
ora.asm ora.asm.type ONLINE ONLINE rac1
ora.cvu ora.cvu.type ONLINE ONLINE rac2
ora.gsd ora.gsd.type ONLINE OFFLINE
ora....network ora....rk.type ONLINE ONLINE rac1
ora.oc4j ora.oc4j.type ONLINE ONLINE rac2
ora.ons ora.ons.type ONLINE ONLINE rac1
ora....SM1.asm application ONLINE ONLINE rac1
ora....C1.lsnr application ONLINE ONLINE rac1
ora.rac1.gsd application ONLINE OFFLINE
ora.rac1.ons application ONLINE ONLINE rac1
ora.rac1.vip ora....t1.type ONLINE ONLINE rac1
ora....SM2.asm application ONLINE ONLINE rac2
ora....C2.lsnr application ONLINE ONLINE rac2
ora.rac2.gsd application ONLINE OFFLINE
ora.rac2.ons application ONLINE ONLINE rac2
ora.rac2.vip ora....t1.type ONLINE ONLINE rac2
ora.racdb.db ora....se.type ONLINE ONLINE rac1
ora.scan1.vip ora....ip.type ONLINE ONLINE rac1
[grid@rac1 ~]$
-------查看状态
SQL> set line 9999
SQL> select dbid,name,current_scn,protection_mode,database_role,force_logging,open_mode,switchover_status from gv$database;
DBID NAME CURRENT_SCN PROTECTION_MODE DATABASE_ROLE FOR OPEN_MODE SWITCHOVER_STATUS
---------- --------- ----------- -------------------- ---------------- --- -------------------- --------------------
857466254 RACDB 2834308 MAXIMUM PERFORMANCE PHYSICAL STANDBY YES MOUNTED RECOVERY NEEDED
857466254 RACDB 2834308 MAXIMUM PERFORMANCE PHYSICAL STANDBY YES MOUNTED RECOVERY NEEDED
SQL>
1.1.1.8 ⑧ 原 RAC 主库启动 redo apply：
SQL> alter database recover managed standby database using current logfile disconnect from session;
Database altered.
1.1.1.9 ⑨ 原 RAC 主库停止 redo apply，并将 RAC 主库所有节点以 READ ONLY 打开：
SQL> alter database recover managed standby database cancel;
Database altered.
SQL> select dbid,name,current_scn,protection_mode,database_role,force_logging,open_mode,switchover_status from gv$database;
DBID NAME CURRENT_SCN PROTECTION_MODE DATABASE_ROLE FOR OPEN_MODE SWITCHOVER_STATUS
---------- --------- ----------- -------------------- ---------------- --- -------------------- --------------------
857466254 RACDB 2838735 MAXIMUM PERFORMANCE PHYSICAL STANDBY YES MOUNTED NOT ALLOWED
857466254 RACDB 2838735 MAXIMUM PERFORMANCE PHYSICAL STANDBY YES MOUNTED NOT ALLOWED
SQL> alter database open;
Database altered.
SQL> select dbid,name,current_scn,protection_mode,database_role,force_logging,open_mode,switchover_status from gv$database;
DBID NAME CURRENT_SCN PROTECTION_MODE DATABASE_ROLE FOR OPEN_MODE SWITCHOVER_STATUS
---------- --------- ----------- -------------------- ---------------- --- -------------------- --------------------
857466254 RACDB 2838735 MAXIMUM PERFORMANCE PHYSICAL STANDBY YES MOUNTED NOT ALLOWED
857466254 RACDB 2838735 MAXIMUM PERFORMANCE PHYSICAL STANDBY YES READ ONLY NOT ALLOWED
SQL> select dbid,inst_id,name,current_scn,protection_mode,database_role,force_logging,open_mode,switchover_status from gv$database;
DBID INST_ID NAME CURRENT_SCN PROTECTION_MODE DATABASE_ROLE FOR OPEN_MODE SWITCHOVER_STATUS
---------- ---------- --------- ----------- -------------------- ---------------- --- -------------------- --------------------
857466254 2 RACDB 2838735 MAXIMUM PERFORMANCE PHYSICAL STANDBY YES READ ONLY NOT ALLOWED
857466254 1 RACDB 2838735 MAXIMUM PERFORMANCE PHYSICAL STANDBY YES MOUNTED NOT ALLOWED
SQL>
---- 启动第二个节点后查看：
SQL> select dbid,inst_id,name,current_scn,protection_mode,database_role,force_logging,open_mode,switchover_status from gv$database;
DBID INST_ID NAME CURRENT_SCN PROTECTION_MODE DATABASE_ROLE FOR OPEN_MODE SWITCHOVER_STATUS
---------- ---------- --------- ----------- -------------------- ---------------- --- -------------------- --------------------
857466254 2 RACDB 2838735 MAXIMUM PERFORMANCE PHYSICAL STANDBY YES READ ONLY NOT ALLOWED
857466254 1 RACDB 2838735 MAXIMUM PERFORMANCE PHYSICAL STANDBY YES READ ONLY NOT ALLOWED
SQL>
----dg库查看：
SQL> select dbid,name,current_scn,protection_mode,database_role,force_logging,open_mode,switchover_status from gv$database;
DBID NAME CURRENT_SCN PROTECTION_MODE DATABASE_ROLE FOR OPEN_MODE SWITCHOVER_STATUS
---------- --------- ----------- -------------------- ---------------- --- -------------------- --------------------
857466254 RACDB 2839188 MAXIMUM PERFORMANCE PRIMARY YES READ WRITE TO STANDBY
SQL>
1.1.1.10 ⑩测试切换后的效果
dg主机建表：
SQL> create table test_dg(id number);
Table created.
rac主机库查看：
SQL> desc test_dg
ERROR:
ORA-04043: object test_dg does not exist
SQL> alter database recover managed standby database using current logfile disconnect from session;
Database altered.
SQL> desc test_dg
Name Null? Type
----------------------------------------- -------- ----------------------------
ID NUMBER
dg主机插入数据：
SQL> insert into test_dg values(100);
1 row created.
SQL> commit;
Commit complete.
SQL>
rac库查看：
SQL> select * from test_dg;
ID
----------
100
SQL>
---dg库删除
SQL> drop table test_dg purge;
Table dropped.
SQL>
--新备库查看
SQL> select * from test_dg;
select * from test_dg
*
ERROR at line 1:
ORA-00942: table or view does not exist
SQL>
至此，说明切换成功完成。
1.1.2 单实例主库，RAC备库角色切换
即，将新 RAC 备库切换为主库，新单实例主库切换为备库：
1.1.2.1 ① 新主库（单实例库）状态查看：
SQL> show parameter instance_name
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
instance_name string phydb
SQL> select dbid,name,current_scn,protection_mode,database_role,force_logging,open_mode,switchover_status from gv$database;
DBID NAME CURRENT_SCN PROTECTION_MODE DATABASE_ROLE FOR OPEN_MODE SWITCHOVER_STATUS
---------- --------- ----------- -------------------- ---------------- --- -------------------- --------------------
857466254 RACDB 2840504 MAXIMUM PERFORMANCE PRIMARY YES READ WRITE TO STANDBY
SQL>
1.1.2.2 ② 新备库（RAC 库）状态查看：
SQL> select inst_id, dbid,name,current_scn,protection_mode,database_role,force_logging,open_mode,switchover_status from gv$database;
INST_ID DBID NAME CURRENT_SCN PROTECTION_MODE DATABASE_ROLE FOR OPEN_MODE SWITCHOVER_STATUS
---------- ---------- ---------- ----------- -------------------- ---------------- --- -------------------- --------------------
1 857466254 RACDB 2840572 MAXIMUM PERFORMANCE PHYSICAL STANDBY YES READ ONLY WITH APPLY NOT ALLOWED
2 857466254 RACDB 2840572 MAXIMUM PERFORMANCE PHYSICAL STANDBY YES READ ONLY WITH APPLY NOT ALLOWED
SQL>
1.1.2.3 ③ 新备库（RAC 库）停止节点 2：
SQL> show parameter instance_name
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
instance_name string racdb2
SQL> select dbid,inst_id,name,current_scn,protection_mode,database_role,force_logging,open_mode,switchover_status from gv$database;
DBID INST_ID NAME CURRENT_SCN PROTECTION_MODE DATABASE_ROLE FOR OPEN_MODE SWITCHOVER_STATUS
---------- ---------- --------- ----------- -------------------- ---------------- --- -------------------- --------------------
857466254 2 RACDB 2840675 MAXIMUM PERFORMANCE PHYSICAL STANDBY YES READ ONLY WITH APPLY NOT ALLOWED
857466254 1 RACDB 2840675 MAXIMUM PERFORMANCE PHYSICAL STANDBY YES READ ONLY WITH APPLY NOT ALLOWED
SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> select inst_id, dbid,name,current_scn,protection_mode,database_role,force_logging,open_mode,switchover_status from gv$database;
INST_ID DBID NAME CURRENT_SCN PROTECTION_MODE DATABASE_ROLE FOR OPEN_MODE SWITCHOVER_STATUS
---------- ---------- ---------- ----------- -------------------- ---------------- --- -------------------- --------------------
1 857466254 RACDB 2861126 MAXIMUM PERFORMANCE PHYSICAL STANDBY YES READ ONLY WITH APPLY TO PRIMARY
SQL>
1.1.2.4 ④ 新主库（单实例库）切换到备库：
SQL> show parameter instance_name
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
instance_name string phydb
SQL> select dbid,name,current_scn,protection_mode,database_role,force_logging,open_mode,switchover_status from gv$database;
DBID NAME CURRENT_SCN PROTECTION_MODE DATABASE_ROLE FOR OPEN_MODE SWITCHOVER_STATUS
---------- --------- ----------- -------------------- ---------------- --- -------------------- --------------------
857466254 RACDB 2841031 MAXIMUM PERFORMANCE PRIMARY YES READ WRITE TO STANDBY
SQL> alter database commit to switchover to physical standby with session shutdown;
Database altered.
SQL> select dbid,name,current_scn,protection_mode,database_role,force_logging,open_mode,switchover_status from gv$database;
DBID NAME CURRENT_SCN PROTECTION_MODE DATABASE_ROLE FOR OPEN_MODE SWITCHOVER_STATUS
---------- --------- ----------- -------------------- ---------------- --- -------------------- --------------------
857466254 RACDB 2841153 MAXIMUM PERFORMANCE PHYSICAL STANDBY YES READ WRITE RECOVERY NEEDED
SQL>
1.1.2.5 ⑤新备库（RAC 库）节点 1 切换到主库：
SQL> alter database recover managed standby database cancel;
Database altered.
SQL> select inst_id, dbid,name,current_scn,protection_mode,database_role,force_logging,open_mode,switchover_status from gv$database;
INST_ID DBID NAME CURRENT_SCN PROTECTION_MODE DATABASE_ROLE FOR OPEN_MODE SWITCHOVER_STATUS
---------- ---------- ---------- ----------- -------------------- ---------------- --- -------------------- --------------------
1 857466254 RACDB 2861126 MAXIMUM PERFORMANCE PHYSICAL STANDBY YES READ ONLY TO PRIMARY
--- 这里最好先把库修改为mount状态再切换，不然事务很大的话会非常的慢
SQL> alter database commit to switchover to primary;
Database altered.
SQL> select inst_id, dbid,name,current_scn,protection_mode,database_role,force_logging,open_mode,switchover_status from gv$database;
INST_ID DBID NAME CURRENT_SCN PROTECTION_MODE DATABASE_ROLE FOR OPEN_MODE SWITCHOVER_STATUS
---------- ---------- ---------- ----------- -------------------- ---------------- --- -------------------- --------------------
1 857466254 RACDB 0 MAXIMUM PERFORMANCE PRIMARY YES MOUNTED NOT ALLOWED
SQL>
1.1.2.6 ⑥ 新备库(RAC 库)全部启动所有节点：
节点一：
SQL> alter database open;
Database altered.
SQL> show parameter instance_name
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
instance_name string racdb1
SQL>
节点二：
SQL> startup
ORACLE instance started.
Total System Global Area 1336176640 bytes
Fixed Size 2228144 bytes
Variable Size 1107296336 bytes
Database Buffers 218103808 bytes
Redo Buffers 8548352 bytes
Database mounted.
Database opened.
SQL> show parameter instance_name
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
instance_name string racdb2
SQL>
SQL> select dbid,inst_id,name,current_scn,protection_mode,database_role,force_logging,open_mode,switchover_status from gv$database;
DBID INST_ID NAME CURRENT_SCN PROTECTION_MODE DATABASE_ROLE FOR OPEN_MODE SWITCHOVER_STATUS
---------- ---------- --------- ----------- -------------------- ---------------- --- -------------------- --------------------
857466254 1 RACDB 2864440 MAXIMUM PERFORMANCE PRIMARY YES READ WRITE RESOLVABLE GAP
857466254 2 RACDB 2864440 MAXIMUM PERFORMANCE PRIMARY YES READ WRITE RESOLVABLE GAP
SQL>
1.1.2.7 ⑦ 新备库（单实例库）重新启动并开始 redo apply：
注意备库必须关闭然后重启：
[oracle@dg ~]$ sqlplus / as sysdba
SQL*Plus: Release 11.2.0.3.0 Production on Mon Nov 10 17:18:12 2014
Copyright (c) 1982, 2011, Oracle. All rights reserved.
Connected to an idle instance.
SQL> startup
ORACLE instance started.
Total System Global Area 839282688 bytes
Fixed Size 2233000 bytes
Variable Size 574623064 bytes
Database Buffers 260046848 bytes
Redo Buffers 2379776 bytes
Database mounted.
Database opened.
SQL> alter database recover managed standby database using current logfile disconnect from session;
Database altered.
SQL> host ps -ef|grep mrp
oracle 31367 1 0 17:19 ? 00:00:00 ora_mrp0_phydb
oracle 31375 31168 0 17:20 pts/3 00:00:00 /bin/bash -c ps -ef|grep mrp
oracle 31377 31375 0 17:20 pts/3 00:00:00 grep mrp
SQL>
至此，完成一次角色切换，即将新的备库（RAC 库）切换成主库，新的备库（单实例库）又重新切换为物理备库，回到最初的状态！！！
1.1.2.8 ⑧ 测试切换后的效果
--rac主库
SQL> select inst_id, dbid,name,current_scn,protection_mode,database_role,force_logging,open_mode,switchover_status from gv$database;
INST_ID DBID NAME CURRENT_SCN PROTECTION_MODE DATABASE_ROLE FOR OPEN_MODE SWITCHOVER_STATUS
---------- ---------- ---------- ----------- -------------------- ---------------- --- -------------------- --------------------
1 857466254 RACDB 2865147 MAXIMUM PERFORMANCE PRIMARY YES READ WRITE TO STANDBY
2 857466254 RACDB 2865147 MAXIMUM PERFORMANCE PRIMARY YES READ WRITE TO STANDBY
SQL>
--dg备库
SQL> select dbid,name,current_scn,protection_mode,database_role,force_logging,open_mode,switchover_status from gv$database;
DBID NAME CURRENT_SCN PROTECTION_MODE DATABASE_ROLE FOR OPEN_MODE SWITCHOVER_STATUS
---------- --------- ----------- -------------------- ---------------- --- -------------------- --------------------
857466254 RACDB 2861129 MAXIMUM PERFORMANCE PHYSICAL STANDBY YES READ ONLY WITH APPLY NOT ALLOWED
SQL>
-------rac主库建表
SQL> create table test_dg(id number);
Table created.
SQL> select * from test_dg;
no rows selected
----dg备库查看，由于是刚切换过来的原因，这里可能需要等待几分钟才可以查询到：
SQL> select * from test_dg;
no rows selected
SQL>
---rac主库插入数据
SQL> insert into test_dg values(200);
1 row created.
SQL> commit;
Commit complete.
SQL> select * from test_dg;
ID
----------
200
--dg库查看：
SQL> select * from test_dg;
ID
----------
200
SQL>