01: 与做备库一样,配置好 监听文件 密码文件 网络文件 并且动好监听. 注意必要的目录结构.然后从主库,备库1 都能用SYS用户登陆到备库2 表示通道是联通有效的.

02: 从主库生成个最新的INIT.ORA文件,复制到备库2 修改参数文件的参数.

然后 启动 并且生成SPFILE文件再启动
dg2:

startup nomount pfile='/home/oracle/initdg.ora';
  create spfile from pfile='/home/oracle/initdg.ora';
  shutdown immeidate;
  startup nomount;

主库 设置下面两个参数
pd:

ALTER SYSTEM SET LOG_ARCHIVE_DEST_3='SERVICE=dg2 LGWR ASYNC AFFIRM VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE) DB_UNIQUE_NAME=dg2' scope=both;
ALTER SYSTEM SET LOG_ARCHIVE_CONFIG='DG_CONFIG=(pd,dg1,dg2)' scope=both;

在主库上复制备库到备库2上,源数据库必须是主库
pd:

rman target sys/pbs123@orcl_pd auxiliary sys/pbs123@orcl_st3

RMAN> duplicate target database for standby nofilenamecheck from active database;
————————输出省略——————

复制过程中报得错误大部分是路径错误,没有建相应的目录

pd:

alter system set log_archive_dest_state_3=enable scope=both;

开启只读模式完成数据恢复
dg2:

alter database open read only;  
alter database recover managed standby database using current logfile disconnect from session;  
ALTER SYSTEM SET log_archive_dest_1='LOCATION=/u01/ora_archive VALID_FOR=(ALL_LOGFILES,ALL_ROLES) DB_UNIQUE_NAME=dg2' scope=both;

设置好参数,注意服务器是DG1

alter system set fal_server='dg1';  
alter system set fal_client='dg2';

数据同步完了后…

主库pd:

alter system set log_archive_dest_state_3=defer scope=both;

备库1
dg1:

ALTER SYSTEM SET LOG_ARCHIVE_DEST_3='SERVICE=dg2 LGWR ASYNC AFFIRM VALID_FOR=(ONLINE_LOGFILES,dg2)' scope=both;

测试下:
主库:
sql> create table zfk_all_objects as select * from dba_objects;

Table created.

Elapsed: 00:00:01.80

备库1:
sql> select count(*) from zfk_all_objects;

COUNT(*)

73680

备库2:
sql> select count(*) from zfk_all_objects;

COUNT(*)

73680

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注意事项:
1 DG1 设置目的3的时候 应该改成如下
alter system set log_archive_dest_3='SERVICE=dg2LGWR ASYNC AFFIRM valid_for=(standby_logfiles,standby_role) db_unique_name=dg2' scope=BOTH; 
2 只有主库发生了日志切换 DG1才把日志传给DG2

**