在将Data Guard调整为最大保护模式（MAXIMUM PROTECTION ）的时候，遇到了以下的问题ORA-03113: end-of-file on communication channel。

执行过程如下：

SQL> alter database set standby database to maximize PROTECTION;
alter database set standby database to maximize PROTECTION
*
ERROR at line 1:
ORA-01126: database must be mounted in this instance and not open in any instance
SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup mount
ORACLE instance started.
Total System Global Area  390070272 bytes
Fixed Size                  2021024 bytes
Variable Size             142608736 bytes
Database Buffers          243269632 bytes
Redo Buffers                2170880 bytes
Database mounted.
SQL> alter database set standby database to maximize PROTECTION;
Database altered.
SQL> select PROTECTION_MODE,OPEN_MODE,DB_UNIQUE_NAME,DATABASE_ROLE,SWITCHOVER_STATUS from v$database;
PROTECTION_MODE      OPEN_MODE  DB_UNIQUE_NAME                 DATABASE_ROLE    SWITCHOVER_STATUS
-------------------- ---------- ------------------------------ ---------------- --------------------
MAXIMUM PROTECTION   MOUNTED    WENDING                        PRIMARY          TO STANDBY
SQL> alter database open;
alter database open
*
ERROR at line 1:
ORA-03113: end-of-file on communication channel

分析日志：

[oracle@dg1 bdump]$ tail -10f alert_WENDING.log
LGWR: Destination LOG_ARCHIVE_DEST_1 is not serviced by LGWR
LGWR: Minimum of 1 synchronous standby database required
Sat Jan  4 23:05:16 2014
Errors in file /u01/oracle/admin/ORCLDB/bdump/wending_lgwr_10086.trc:
ORA-16072: a minimum of one standby database destination is required
Sat Jan  4 23:05:16 2014
Errors in file /u01/oracle/admin/ORCLDB/bdump/wending_lgwr_10086.trc:
ORA-16072: a minimum of one standby database destination is required
LGWR: terminating instance due to error 16072
Instance terminated by LGWR, pid = 10086

其实，第一步处理过程，应该查询一下log_archive_dest参数，检查一下同步的方式以及AFFIRM 是否设定，其次就是standy log日志是否添加，这一切建立完成以后再进行日志检查。

可能在第一步检查完成之后就已经可以解决问题。

对了，还有一个要开启FLASHBACK_ON ；

分别将FLASHBACK_ON开启。
SQL> select FLASHBACK_ON from v$database;
FLASHBACK_ON
------------------
NO
SQL> alter database flashback on;
Database altered.

添加standy redolog

[oracle@dg2 ~]$ sqlplus / as sysdba
SQL*Plus: Release 10.2.0.1.0 - Production on Sun Jan 5 01:00:35 2014
Copyright (c) 1982, 2005, Oracle.  All rights reserved.
Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - 64bit Production
With the Partitioning, OLAP and Data Mining options
SQL> alter database add standby logfile group 4 ('/u01/oracle/oradata/ORCLDB/stdby_redo04.log') size 50M;
Database altered.
SQL> alter database add standby logfile group 5 ('/u01/oracle/oradata/ORCLDB/stdby_redo05.log') size 50M;
Database altered.
SQL> alter database add standby logfile group 6 ('/u01/oracle/oradata/ORCLDB/stdby_redo06.log') size 50M;
Database altered.

[oracle@dg1 bdump]$ sqlplus / as sysdba
SQL*Plus: Release 10.2.0.1.0 - Production on Sun Jan 5 01:10:32 2014
Copyright (c) 1982, 2005, Oracle.  All rights reserved.
Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - 64bit Production
With the Partitioning, OLAP and Data Mining options
SQL> alter database set standby database to maximize PROTECTION;
alter database set standby database to maximize PROTECTION
*
ERROR at line 1:
ORA-01126: database must be mounted in this instance and not open in any instance
SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup mount
ORACLE instance started.
Total System Global Area  390070272 bytes
Fixed Size                  2021024 bytes
Variable Size             142608736 bytes
Database Buffers          243269632 bytes
Redo Buffers                2170880 bytes
Database mounted.
SQL> alter database set standby database to maximize PROTECTION;
Database altered.
SQL> select PROTECTION_MODE,OPEN_MODE,DB_UNIQUE_NAME,DATABASE_ROLE,SWITCHOVER_STATUS from v$database;
PROTECTION_MODE      OPEN_MODE  DB_UNIQUE_NAME                 DATABASE_ROLE    SWITCHOVER_STATUS
-------------------- ---------- ------------------------------ ---------------- --------------------
MAXIMUM PROTECTION   MOUNTED    WENDING                        PRIMARY          TO STANDBY

设置参数，打开数据库。

SQL>  alter system set log_archive_dest_2 = 'SERVICE=db_phystdby LGWR SYNC VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE) DB_UNIQUE_NAME=PHYSTDBY AFFIRM ';
System altered.
SQL> alter database open;
Database altered.