oracle rac实例切换,RAC+单实例DG的切换
RAC+单实例DG的切换
RAC+单实例DG的搭建过程
之前切换不成功，和参数设置有关。注意的参数是sid=* 之类的，刚搭建好的环境
racdbdg是单实例的，是备库，rac节点是主库。
搭建完毕，切换了一次，刚好主库是单实例的racdbdg，rac节点是备库了。
进行后续的切换
--------------------------------
primary ：racdbdg 单实例
SYS@racdbdg>select database_role,switchover_status from v$database;
DATABASE_ROLE
SWITCHOVER_STATUS
---------------- --------------------
PRIMARY
TO STANDBY
SYS@racdbdg>
Standby ： 是RAC节点
SYS@racdb2>select database_role,switchover_status from v$database;
DATABASE_ROLE
SWITCHOVER_STATUS
---------------- --------------------
PHYSICAL STANDBY NOT ALLOWED
SYS@racdb1>select database_role,switchover_status from v$database;
DATABASE_ROLE
SWITCHOVER_STATUS
---------------- --------------------
PHYSICAL STANDBY NOT ALLOWED
或者这样查询
SYS@racdb2>select inst_id,database_role,switchover_status from gv$database;
INST_ID DATABASE_ROLE SWITCHOVER_STATUS
---------- ---------------- --------------------
2 PHYSICAL STANDBY NOT ALLOWED
1 PHYSICAL STANDBY NOT ALLOWED
--------开始切换
查看主库的状态 在主机 racdbdg上查看 。 是to standby ,可以切换
SYS@racdbdg>select database_role,switchover_status from v$database;
DATABASE_ROLE
SWITCHOVER_STATUS
---------------- --------------------
PRIMARY
TO STANDBY
SYS@racdbdg>
-- 将主库切换到备库状态
alter database commit to switchover to physical standby with session shutdown;
SYS@racdbdg>alter database commit to switchover to physical standby with session shutdown;
Database altered.
将新的备库启动到mount状态，这个时候新的备库是关闭状态，启动后，状态是备库
SYS@racdbdg>archive log list
ORA-01012: not logged on
SYS@racdbdg>conn / as sysdba
Connected to an idle instance.
SYS@racdbdg>startup mount
ORACLE instance started.
Total System Global Area 1235959808 bytes
Fixed Size
2252784 bytes
Variable Size
922746896 bytes
Database Buffers
301989888 bytes
Redo Buffers
8970240 bytes
Database mounted.
SYS@racdbdg>
SYS@racdbdg>select database_role from v$database;
DATABASE_ROLE
----------------
PHYSICAL STANDBY
SYS@racdbdg>
-- 将原备库切换为主库。在rac 任意一个节点上执行
-- 查看rac节点的状态，是可以切换的
SYS@racdb1>select database_role,switchover_status from v$database;
DATABASE_ROLE
SWITCHOVER_STATUS
---------------- --------------------
PHYSICAL STANDBY TO PRIMARY
SYS@racdb2>select inst_id,database_role,switchover_status from gv$database;
INST_ID DATABASE_ROLE SWITCHOVER_STATUS
---------- ---------------- --------------------
1 PHYSICAL STANDBY SESSIONS ACTIVE
2 PHYSICAL STANDBY SESSIONS ACTIVE
SYS@racdb2>select database_role,switchover_status from v$database;
DATABASE_ROLE
SWITCHOVER_STATUS
---------------- --------------------
PHYSICAL STANDBY TO PRIMARY
SYS@racdb2>
-- 进行切换，在任何一个节点执行。其中另一个节点，会自动切换为mount状态
--在节点2上执行：
SYS@racdb2>alter database commit to switchover to primary with session shutdown ;
Database altered.
SYS@racdb2>select switchover_status ,open_mode,database_role from v$database;
SWITCHOVER_STATUS OPEN_MODE
DATABASE_ROLE
-------------------- -------------------- ----------------
NOT ALLOWED
MOUNTED
PRIMARY
SYS@racdb2>alter database open;
Database altered.
SYS@racdb2>
--另一个节点状态
SYS@racdb1>archive log list
ORA-03135: connection lost contact
SYS@racdb1>conn / as sysdba
Connected.
SYS@racdb1>
-- 这个时候，主库是rac。备库是单实例的racdbdg了 在主库上插入数据，备库查询
SYS@racdb2>select count(*) from t;
COUNT(*)
----------
6
SYS@racdb2>insert into t values(7);
1 row created.
SYS@racdb2>commit;
Commit complete.
SYS@racdbdg>select * from t;
ID
----------
1
2
3
4
5
6
7
7 rows selected.
------- 再切换一次，主备切换
现在的主库是双节点的rac， 备库是单实例的racdbdg 。再切换一次，把主库切换成单节点，备库切换成rac
SYS@racdb1>select database_role,switchover_status from v$database;
DATABASE_ROLE
SWITCHOVER_STATUS
---------------- --------------------
PRIMARY
TO STANDBY
SYS@racdb1>alter database commit to switchover to physical standby with session shutdown;
Database altered.
SYS@racdb1>
切换为备库后，原来的双节点的主库变成备库，两个节点都被关闭。需要mount
SYS@racdb1>select open_mode ,database_role from v$database;
select open_mode ,database_role from v$database
*
ERROR at line 1:
ORA-01034: ORACLE not available
Process ID: 9039
Session ID: 32 Serial number: 19
SYS@racdb1>conn / as sysdba
Connected to an idle instance.
SYS@racdb1>startup mount;
ORACLE instance started.
Total System Global Area 1235959808 bytes
Fixed Size
2252784 bytes
Variable Size
1090519056 bytes
Database Buffers
134217728 bytes
Redo Buffers
8970240 bytes
Database mounted.
SYS@racdb1>select open_mode ,database_role from v$database;
OPEN_MODE
DATABASE_ROLE
-------------------- ----------------
MOUNTED
PHYSICAL STANDBY
SYS@racdb1>
-- 切换单实例的备库为主库：
SYS@racdbdg>select database_role,switchover_status from v$database;
DATABASE_ROLE
SWITCHOVER_STATUS
---------------- --------------------
PHYSICAL STANDBY TO PRIMARY
SYS@racdbdg>
SYS@racdbdg>select database_role,switchover_status from v$database;
DATABASE_ROLE
SWITCHOVER_STATUS
---------------- --------------------
PHYSICAL STANDBY TO PRIMARY
SYS@racdbdg>alter database commit to switchover to primary with session shutdown ;
Database altered.
Database altered.
SYS@racdbdg>conn / as sysdba
Connected.
SYS@racdbdg>select database_role,switchover_status from v$database;
DATABASE_ROLE
SWITCHOVER_STATUS
---------------- --------------------
PRIMARY
NOT ALLOWED
SYS@racdbdg>alter database open;
Database altered.
SYS@racdbdg>
--- 验证 主库插入数据
SYS@racdbdg>select count(*) from t;
COUNT(*)
----------
8
SYS@racdbdg>insert into t values(9);
1 row created.
SYS@racdbdg>commit;
Commit complete.
SYS@racdbdg>
-- 备库查询
SYS@racdb2>archive log list
Database log mode
Archive Mode
Automatic archival
Enabled
Archive destination
+FRA
Oldest online log sequence 0
Next log sequence to archive 0
Current log sequence
0
SYS@racdb2>archive log list
Database log mode
Archive Mode
Automatic archival
Enabled
Archive destination
+FRA
Oldest online log sequence 0
Next log sequence to archive 0
Current log sequence
0
SYS@racdb2>select count(*) from t;
COUNT(*)
----------
9
SYS@racdb2>
SYS@racdb1>archive log list
Database log mode
Archive Mode
Automatic archival
Enabled
Archive destination
+FRA
Oldest online log sequence 23
Next log sequence to archive 0
Current log sequence
23
SYS@racdb1>
SYS@racdbdg>archive log list
Database log mode
Archive Mode
Automatic archival
Enabled
Archive destination
/u01/archivelog
Oldest online log sequence 22
Next log sequence to archive 23
Current log sequence
23
SYS@racdbdg>
从上面可以看到，切换成功了 。
从alert log中看到的一些信息。说明，在搭建的时候，要考虑sid
Archived Log entry 91 added for thread 2 sequence 16 ID 0x396d1acf dest 1:
Fri Jan 19 15:44:15 2018
ALTER SYSTEM SET log_archive_dest_state_2='ENABLE' SCOPE=MEMORY SID='*';
Fri Jan 19 15:45:43 2018
Thread 1 cannot allocate new log, sequence 23
Checkpoint not complete
Current log# 1 seq# 22 mem# 0: /u01/app/oracle/oradata/racdbdg/group_1.257.965769287
******************************************************************
LGWR: Setting 'active' archival for destination LOG_ARCHIVE_DEST_2
******************************************************************
LGWR: Standby redo logfile selected for thread 1 sequence 23 for destination LOG_ARCHIVE_DEST_2
Thread 1 advanced to log sequence 23 (LGWR switch)
Current log# 2 seq# 23 mem# 0: /u01/app/oracle/oradata/racdbdg/group_2.258.965769287
Fri Jan 19 15:45:45 2018
Archived Log entry 94 added for thread 1 sequence 22 ID 0x396d1acf dest 1:
总结
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