Oracle一对多(一主多备)的DG环境如何进行switchover切换？

老苏畅谈运维2024-08-13 15:41

本文主要分享Oracle一对多(一主多备)的DG环境的switchover切换，如何进行主从切换，切换后怎么恢复正常同步？

1、环境说明

本文的环境为一主两备，数据库版本为11.2.0.4，主要信息如下：

数据库IP db_unique_name 原角色（切换前） 目标角色（切换后）
10.10.10.160 ora11g 主库 备库
10.10.10.41 dgora11g 备库 主库
10.10.10.47 sbora11g 备库 备库

说明：

（1）当前主库为10.10.10.160，10.10.10.41 和10.10.10.47是它的两个备库。

​（2）switchover切换后，10.10.10.41变为主库，10.10.10.160和10.10.10.47成为它的两个备库。

2、主要参数配置

以下是相关数据库的主要参数配置信息（以db_unique_name进行区分）：

ora11g:

复制代码 
set linesize 500 pages 0
col value for a100
col name for a50
select name, value
from v$parameter
where name in ('db_name','db_unique_name',
'log_archive_config',
'log_archive_dest_1','log_archive_dest_2',
'log_archive_dest_state_1',
'log_archive_dest_state_2',
'remote_login_passwordfile',
'log_archive_format',
'log_archive_max_processes',
'fal_server','db_file_name_convert',
'log_file_name_convert',
'standby_file_management')
/

db_file_name_convert				   /u01/oradata/dgora11g, /u01/oradata/ora11g, /u01/oradata/sbora11g, /u01/oradata/ora11g
log_file_name_convert				   /u01/oradata/dgora11g, /u01/oradata/ora11g, /u01/oradata/sbora11g, /u01/oradata/ora11g
log_archive_dest_1				   location=/u01/oradata/archivelog VALID_FOR=(ALL_LOGFILES,ALL_ROLES) db_unique_name=ora11g
log_archive_dest_2				   SERVICE=dgora11g LGWR ASYNC VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE) db_unique_name=dgora11g
log_archive_dest_state_1			   ENABLE
log_archive_dest_state_2			   ENABLE
fal_server					   dgora11g, sbora11g
log_archive_config				   DG_CONFIG=(ora11g,dgora11g,sbora11g)
log_archive_format				   %t_%s_%r.dbf
log_archive_max_processes			   4
standby_file_management 			   AUTO
remote_login_passwordfile			   EXCLUSIVE
db_name 					   ora11g
db_unique_name					   ora11g

dgora11g:

复制代码 
db_file_name_convert				   /u01/oradata/ora11g, /u01/oradata/dgora11g
log_file_name_convert				   /u01/oradata/ora11g, /u01/oradata/dgora11g
log_archive_dest_1				   location=/u01/oradata/archivelog VALID_FOR=(ALL_LOGFILES,ALL_ROLES) db_unique_name=dgora11g
log_archive_dest_2				   SERVICE=ora11g LGWR ASYNC VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE) db_unique_name=ora11g
log_archive_dest_state_1			   ENABLE
log_archive_dest_state_2			   ENABLE
fal_server					   ora11g
log_archive_config				   DG_CONFIG=(ora11g,dgora11g)
log_archive_format				   %t_%s_%r.dbf
log_archive_max_processes			   4
standby_file_management 			   AUTO
remote_login_passwordfile			   EXCLUSIVE
db_name 					   ora11g
db_unique_name					   dgora11g

sbora11g:

复制代码 
db_file_name_convert				   /u01/oradata/ora11g, /u01/oradata/sbora11g
log_file_name_convert				   /u01/oradata/ora11g, /u01/oradata/sbora11g
log_archive_dest_1				   location=/u01/oradata/archivelog VALID_FOR=(ALL_LOGFILES,ALL_ROLES) db_unique_name=sbora11g
log_archive_dest_2				   SERVICE=ora11g LGWR ASYNC VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE) db_unique_name=ora11g
log_archive_dest_state_1			   ENABLE
log_archive_dest_state_2			   ENABLE
fal_server					   ora11g
log_archive_config				   DG_CONFIG=(ora11g,sbora11g)
log_archive_format				   %t_%s_%r.dbf
log_archive_max_processes			   4
standby_file_management 			   AUTO
remote_login_passwordfile			   EXCLUSIVE
db_name 					   ora11g
db_unique_name					   sbora11g

3、切换前检查

切换前，确认备库同步情况，有没有延迟

dgora11g:

复制代码 
sys@dgora11g> select value from v$dataguard_stats where name='transport lag';

VALUE
----------------------------------------------------------------
+00 00:00:00

sys@dgora11g> select value from v$dataguard_stats where name='apply lag'; 

VALUE
----------------------------------------------------------------
+00 00:00:00

--检查最新归档到的日志号及是否有gap

sys@dgora11g> SELECT UNIQUE THREAD# AS THREAD, MAX(SEQUENCE#) OVER (PARTITION BY thread#) AS LAST from V$ARCHIVED_LOG;

    THREAD	 LAST
---------- ----------
	 1	  289

sys@dgora11g> SELECT THREAD#, LOW_SEQUENCE#, HIGH_SEQUENCE# FROM V$ARCHIVE_GAP;

no rows selected

sbora11g:

复制代码 
sys@sbora11g > select value from v$dataguard_stats where name='transport lag';

VALUE
----------------------------------------------------------------
+00 00:00:00

sys@sbora11g > select value from v$dataguard_stats where name='apply lag';

VALUE
----------------------------------------------------------------
+00 00:00:00
sys@sbora11g > SELECT UNIQUE THREAD# AS THREAD, MAX(SEQUENCE#) OVER (PARTITION BY thread#) AS LAST from V$ARCHIVED_LOG;

    THREAD	 LAST
---------- ----------
	 1	  289

sys@sbora11g > SELECT THREAD#, LOW_SEQUENCE#, HIGH_SEQUENCE# FROM V$ARCHIVE_GAP;

no rows selected

检查确认两个备库实时同步，没有延时后，才能切换。

4、switchover切换

在切换时，在主库上是不可以选择我要切换到哪个备库的，这个选择是在备库上选择的，下面进行SWITCHOVER切换。

--主库状态

复制代码 
sys@ora11g> col name for a10;
sys@ora11g> set linesize 100;
sys@ora11g> select name,open_mode, database_role, switchover_status, force_logging, dataguard_broker, guard_status from v$database;

NAME	   OPEN_MODE		DATABASE_ROLE	 SWITCHOVER_STATUS    FOR DATAGUAR GUARD_S
---------- -------------------- ---------------- -------------------- --- -------- -------
ORA11G	   READ WRITE		PRIMARY 	 TO STANDBY	      YES DISABLED NONE

--备库状态

dgora11g:

复制代码 
sys@dgora11g> col name for a10;
sys@dgora11g> set linesize 100;
sys@dgora11g> select name,open_mode, database_role, switchover_status, force_logging, dataguard_broker, guard_status from v$database;

NAME	   OPEN_MODE		DATABASE_ROLE	 SWITCHOVER_STATUS    FOR DATAGUAR GUARD_S
---------- -------------------- ---------------- -------------------- --- -------- -------
ORA11G	   MOUNTED		PHYSICAL STANDBY NOT ALLOWED	      YES DISABLED NONE

sbora11g:

复制代码 
sys@sbora11g > col name for a10;
sys@sbora11g > set linesize 100;
sys@sbora11g > select name,open_mode, database_role, switchover_status, force_logging, dataguard_broker, guard_status from v$database;

NAME	   OPEN_MODE		DATABASE_ROLE	 SWITCHOVER_STATUS    FOR DATAGUAR GUARD_S
---------- -------------------- ---------------- -------------------- --- -------- -------
ORA11G	   MOUNTED		PHYSICAL STANDBY NOT ALLOWED	      YES DISABLED NONE

--将主库转为物理备库

ora11g:

复制代码 
alter database commit to switchover to physical standby with session shutdown;

切换后，这个数据库已经备关闭，启动数据库，这个数据库已经变为备库，启动MRP进程。

复制代码 
sys@ora11g> startup;
ORACLE instance started.

Total System Global Area 3691200512 bytes
Fixed Size		    2258680 bytes
Variable Size		 1392511240 bytes
Database Buffers	 2281701376 bytes
Redo Buffers		   14729216 bytes
Database mounted.
Database opened.
sys@ora11g> alter database recover managed standby database using current logfile disconnect from session;

Database altered.

或 alter database recover managed standby database using current logfile disconnect from session parallel 4; 

--检查状态，可以看到已变为从库
sys@ora11g> select name,open_mode, database_role, switchover_status, force_logging, dataguard_broker, guard_status from v$database;

NAME	   OPEN_MODE		DATABASE_ROLE	 SWITCHOVER_STATUS    FOR DATAGUAR GUARD_S
---------- -------------------- ---------------- -------------------- --- -------- -------
ORA11G	   READ ONLY WITH APPLY PHYSICAL STANDBY TO PRIMARY	      YES DISABLED NONE

PS：主库切换后，两个备库均变为TO PRIMARY状态，这时就要选择切换哪个备库为主库了。

dgora11g:

复制代码 
sys@dgora11g> col name for a10;
sys@dgora11g> set linesize 100;
sys@dgora11g> select name,open_mode, database_role, switchover_status, force_logging, dataguard_broker, guard_status from v$database;

NAME	   OPEN_MODE		DATABASE_ROLE	 SWITCHOVER_STATUS    FOR DATAGUAR GUARD_S
---------- -------------------- ---------------- -------------------- --- -------- -------
ORA11G	   MOUNTED		PHYSICAL STANDBY TO PRIMARY	      YES DISABLED NONE

sbora11g:

复制代码 
sys@sbora11g > col name for a10;
sys@sbora11g > set linesize 100;
sys@sbora11g > select name,open_mode, database_role, switchover_status, force_logging, dataguard_broker, guard_status from v$database;

NAME	   OPEN_MODE		DATABASE_ROLE	 SWITCHOVER_STATUS    FOR DATAGUAR GUARD_S
---------- -------------------- ---------------- -------------------- --- -------- -------
ORA11G	   MOUNTED		PHYSICAL STANDBY TO PRIMARY	      YES DISABLED NONE

--备库切换成主库

这里选择sbora11g这个备库切换为主库：

复制代码 
sys@sbora11g > alter database commit to switchover to primary with session shutdown;

Database altered.

sys@sbora11g > alter database open;

Database altered.

sys@sbora11g > select name,open_mode, database_role, switchover_status, force_logging, dataguard_broker, guard_status from v$database;

NAME	   OPEN_MODE		DATABASE_ROLE	 SWITCHOVER_STATUS    FOR DATAGUAR GUARD_S
---------- -------------------- ---------------- -------------------- --- -------- -------
ORA11G	   READ WRITE		PRIMARY 	 TO STANDBY	      YES DISABLED NONE

5、新主库参数调整

log_archive_config、log_archive_dest_3还需加上从库dgora11g

复制代码 
sys@sbora11g > show parameter archive;

NAME				     TYPE	 VALUE
------------------------------------ ----------- ------------------------------
archive_lag_target		     integer	 0
log_archive_config		     string	 DG_CONFIG=(ora11g,sbora11g)
log_archive_dest		     string
log_archive_dest_1		     string	 location=/u01/oradata/archivel
						 og VALID_FOR=(ALL_LOGFILES,ALL
						 _ROLES) db_unique_name=sbora11
						 g
log_archive_dest_10		     string
log_archive_dest_11		     string
log_archive_dest_12		     string
log_archive_dest_13		     string
log_archive_dest_14		     string
log_archive_dest_15		     string
log_archive_dest_16		     string
log_archive_dest_17		     string
log_archive_dest_18		     string
log_archive_dest_19		     string
log_archive_dest_2		     string	 SERVICE=ora11g LGWR ASYNC VALI
						 D_FOR=(ONLINE_LOGFILES,PRIMARY
						 _ROLE) db_unique_name=ora11g
............................................
log_archive_dest_3		     string

--log_archive_config 需将三节点都加上
alter system set log_archive_config='DG_CONFIG=(sbora11g,ora11g,dgora11g)' scope=both sid='*';
alter system set log_archive_dest_3='SERVICE=dgora11g LGWR ASYNC VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE) db_unique_name=dgora11g' scope=both sid='*';
alter system set fal_server='ora11g','dgora11g' scope=both sid='*';
alter system set log_archive_dest_state_3=defer scope=both sid='*';
alter system set log_archive_dest_state_3=enable scope=both sid='*';

6、备库参数调整

--log_archive_config 若未设置，需将三节点都加上

复制代码 
--log_archive_config需将三节点都加上
--dgora11g 修改目标主库为sbora11g
sys@dgora11g> show parameter config;

NAME				     TYPE	 VALUE
------------------------------------ ----------- ------------------------------
dg_broker_config_file1		     string	 /u01/app/oracle/product/11.2.0
						 /db/dbs/dr1dgora11g.dat
dg_broker_config_file2		     string	 /u01/app/oracle/product/11.2.0
						 /db/dbs/dr2dgora11g.dat
log_archive_config		     string	 DG_CONFIG=(ora11g,dgora11g)
sys@dgora11g> alter system set log_archive_config='DG_CONFIG=(sbora11g,ora11g,dgora11g)' scope=both sid='*';

System altered.

--因为dgora11g这个数据库之前的主是ora11g(现在已经变成了备库)，需要把dgora11g的主改成sbora11g。

alter system set log_archive_dest_2='SERVICE=sbora11g LGWR ASYNC VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE) db_unique_name=sbora11g' scope=both sid='*';

alter system set FAL_SERVER='ora11g','sbora11g';

若新的主库不在备库的DG_CONFIG配置里，主库会报错：
ARC3: Archivelog destination LOG_ARCHIVE_DEST_3 disabled: destination Data Guard configuration error
Archived Log entry 29 added for thread 1 sequence 300 ID 0x108ef4ac dest 1:
Fri Aug 09 20:16:12 2024
LNS: Standby redo logfile selected for thread 1 sequence 301 for destination LOG_ARCHIVE_DEST_2

--ora11g备库已经配置，不用修改
sys@ora11g> show parameter log_archive_config;

NAME				     TYPE	 VALUE
------------------------------------ ----------- ------------------------------
log_archive_config		     string	 DG_CONFIG=(ora11g,dgora11g,sbo
						 ra11g)

7、切换后验证

--主库插入测试数据

复制代码 
sys@sbora11g > create table tt0809 as select * from dba_objects;

Table created.

--两备库查询

复制代码 
sys@ora11g> select count(*) from tt0809;

  COUNT(*)
----------
     86266
sys@dgora11g> select count(*) from tt0809;  

  COUNT(*)
----------
     86266

至此主从切换已完成，新主库应与两从库正常同步

关注我，学习更多的数据库知识

相关推荐
老邓计算机毕设6 分钟前
SSM智慧社区家政服务系统80q7o（程序+源码+数据库+调试部署+开发环境)带论文文档1万字以上，文末可获取，系统界面在最后面
数据库·ssm 框架
松涛和鸣1 小时前
72、IMX6ULL驱动实战：设备树（DTS/DTB）+ GPIO子系统+Platform总线
linux·服务器·arm开发·数据库·单片机
likangbinlxa1 小时前
【Oracle11g SQL详解】UPDATE 和 DELETE 操作的正确使用
数据库·sql
r i c k2 小时前
数据库系统学习笔记
数据库·笔记·学习
野犬寒鸦2 小时前
从零起步学习JVM || 第一章：类加载器与双亲委派机制模型详解
java·jvm·数据库·后端·学习
IvorySQL3 小时前
PostgreSQL 分区表的 ALTER TABLE 语句执行机制解析
数据库·postgresql·开源
·云扬·3 小时前
MySQL 8.0 Redo Log 归档与禁用实战指南
android·数据库·mysql
IT邦德3 小时前
Oracle 26ai DataGuard 搭建(RAC到单机)
数据库·oracle
惊讶的猫3 小时前
redis分片集群
数据库·redis·缓存·分片集群·海量数据存储·高并发写
不爱缺氧i4 小时前
完全卸载MariaDB
数据库·mariadb
热门推荐
01GitHub 镜像站点02Claude Code + GLM4.7 避坑指南：解决 Unable to connect to Anthropic services03openclaw配置教程（linux+局域网ollama）04UV安装并设置国内源05AI 规范驱动开发“三剑客”深度对比：Spec-Kit、Kiro 与 OpenSpec 实战指南06Linux下V2Ray安装配置指南07openclaw使用nginx反代部署过程 与disconnected (1008): pairing required解决08Claude Code Skills 实用使用手册09在Trae中使用Pencil MCP10Vue-skills的中文文档