总结： --两台单实例
数据库做DG，数据库版本10.2.0.1.0
1.主库配置为：arch async，备库无STANDBY LOG。
日志中会有：RFS[4]: No standby redo logfiles created
2.主库配置为：arch async，备库有STANDBY LOG，日志中未显示使用。
特殊情况：主库配置为：arch async，备库有STANDBY LOG，备库未打开日志应用 ，日志中有：RFS[8]: Successfully opened standby log 4: '/u01/app/oracle/prod/disk1/standbylog1.log'
3.主库修改参数为：lgwr async,备库有STANDBY LOG，日志如下：
RFS[10]: Successfully opened standby log 4: '/u01/app/oracle/prod/disk1/standbylog1.log'
4.主库修改参数为：log_archive_dest_2 == SERVICE=PROD，只写SERVICE=PROD主库归档不能传送到备库。
实验1：主库配置为：arch async，备库无STANDBY LOG。 1.主库配置及日志：
主库：
SQL> select protection_mode,database_role,protection_level from v$database;
PROTECTION_MODE DATABASE_ROLE PROTECTION_LEVEL
-------------------- ---------------- --------------------
MAXIMUM PERFORMANCE PRIMARY MAXIMUM PERFORMANCE
15:47:43 SQL> show parameter log_archive_dest_2
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
log_archive_dest_2 string SERVICE=prod1 arch async VALI
D_FOR=(ONLINE_LOGFILES,PRIMARY
_ROLE) DB_UNIQUE_NAME=prod1
15:47:49 SQL> select max(sequence#) from v$archived_log;
MAX(SEQUENCE#)
--------------
27
备库：
SQL> select protection_mode,database_role,protection_level from v$database;
PROTECTION_MODE DATABASE_ROLE PROTECTION_LEVEL
-------------------- ---------------- --------------------
MAXIMUM PERFORMANCE PHYSICAL STANDBY MAXIMUM PERFORMANCE
03:48:02 SQL> select group#,thread#,bytes/1024/1024 mb,status from v$standby_log;
no rows selected
03:48:05 SQL> select max(sequence#) from v$archived_log;
MAX(SEQUENCE#)
--------------
27
####################
2.主库做REDO日志切换并查看日志：
15:48:18 SQL> alter system switch logfile;
System altered.
15:49:33 SQL> alter system switch logfile;
System altered.
15:50:11 SQL> select max(sequence#) from v$archived_log;
MAX(SEQUENCE#)
--------------
29
备库已经接收：
03:49:48 SQL> select max(sequence#) from v$archived_log;
MAX(SEQUENCE#)
--------------
29
主库日志:
[oracle@ocm1 ~]$ tail -f alert_PROD.log
Sun Apr 20 15:49:33 2014
Thread 1 advanced to log sequence 29
Current log# 2 seq# 29 mem# 0: /u01/app/oracle/prod/disk1/redo02.log
Current log# 2 seq# 29 mem# 1: /u01/app/oracle/prod/disk2/log2b.log
Sun Apr 20 15:50:11 2014
Thread 1 advanced to log sequence 30
Current log# 3 seq# 30 mem# 0: /u01/app/oracle/prod/disk1/redo03.log
Current log# 3 seq# 30 mem# 1: /u01/app/oracle/prod/disk2/log3b.log
备库日志：
[oracle@ocm2 ~]$ tail -f alert_PROD1.log
RFS[4]: Archived Log: '/u01/app/oracle/prod/arch/1_28_844894247.arc'
Sun Apr 20 03:49:30 2014
Media Recovery Log /u01/app/oracle/prod/arch/1_28_844894247.arc
Media Recovery Waiting for thread 1 sequence 29
Sun Apr 20 03:50:07 2014
RFS[4]: No standby redo logfiles created
RFS[4]: Archived Log: '/u01/app/oracle/prod/arch/1_29_844894247.arc'
Sun Apr 20 03:50:10 2014
Media Recovery Log /u01/app/oracle/prod/arch/1_29_844894247.arc
Media Recovery Waiting for thread 1 sequence 30
##########################################################
实验2：主库配置为：arch async，备库有STANDBY LOG，此时会自动使用备库的STANDBY LOG。 主库配置不变。
备库增加STANDBY LOG：
03:55:04 SQL> alter database recover managed standby database cancel;
Database altered.
03:56:39 SQL> alter database add standby logfile '/u01/app/oracle/prod/disk1/standbylog1.log' size 100m;
Databas |