故障现象：ORACLE DATAGUARD环境搭建完成后启动主库报告如下错误：
Wed Feb 8 23:12:38 2012
LGWR: Error 16047 creating archivelog file 'standby'
Wed Feb 8 23:12:38 2012
Errors in file /home/oracle/admin/port/bdump/port_lns1_1131.trc:
ORA-16047: DGID mismatch between destination setting and standby
Wed Feb 8 23:12:38 2012
FAL[server, ARC1]: Error 16047 creating remote archivelog file 'standby'
FAL[server, ARC1]: FAL archive failed, see trace file.
Wed Feb 8 23:12:38 2012
Errors in file /home/oracle/admin/port/bdump/port_arc1_1125.trc:
ORA-16055: FAL request rejected
ARCH: FAL archive failed. Archiver continuing
经过分析是主库和从库db_unique_name设置不一致引发，
通过show parameter name发现从库的db_unique_name果然和主库预想值不一致，
要求是standby，而实际是port.
主库的参数设置：
ALTER DATABASE FORCE LOGGING;
ALTER SYSTEM SET DB_UNIQUE_NAME=port scope=spfile;
ALTER SYSTEM SET LOG_ARCHIVE_CONFIG='DG_CONFIG=(port,standby)' scope=both;
--主库归档目的地
ALTER SYSTEM SET LOG_ARCHIVE_DEST_1='LOCATION=/home/oracle/archivelog/ VALID_FOR=(ALL_LOGFILES,ALL_ROLES) DB_UNIQUE_NAME=port' scope=both;
--当该库充当主库角色时，设置物理备库redo data的传输目的地
ALTER SYSTEM SET LOG_ARCHIVE_DEST_2='SERVICE=standby LGWR ASYNC VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE) DB_UNIQUE_NAME=standby' scope=spfile;
--许redo传输服务传输数据到目的地，默认是enable
ALTER SYSTEM SET LOG_ARCHIVE_DEST_STATE_1=ENABLE scope=spfile;
ALTER SYSTEM SET LOG_ARCHIVE_DEST_STATE_2=ENABLE scope=spfile;
--exclusive or shared，所有库sys密码要一致，默认是exclusive
ALTER SYSTEM SET REMOTE_LOGIN_PASSWORDFILE=EXCLUSIVE scope=spfile;
--
ALTER SYSTEM SET LOG_ARCHIVE_FORMAT='%t_%s_%r.arc' scope=spfile;
ALTER SYSTEM SET LOG_ARCHIVE_MAX_PROCESSES=4 scope=spfile;
--配置网络服务名，fal_server拷贝丢失的归档文件到这里
ALTER SYSTEM SET FAL_CLIENT=port SCOPE=SPFILE;
--配置网络服务名，假如转换为备库角色时，从这里获取丢失的归档文件
ALTER SYSTEM SET FAL_SERVER=STANDBY SCOPE=SPFILE;
--auto后当主库的datafiles增删时备库也同样自动操作，且会把日志传送到备库standby_archive_dest参数指定的目录下，
--确保该目录存在，如果你的存储采用文件系统没有问题，但是如果采用了裸设备，你就必须将该参数设置为manual
ALTER SYSTEM SET STANDBY_FILE_MANAGEMENT=AUTO SCOPE=SPFILE;
--前为切换后的主库路径，后为切换后的备库路径，如果主备库目录结构完全一样，则无需设定
ALTER SYSTEM SET DB_FILE_NAME_CONVERT='/u01/oracle/oradata/port/','/u01/oracle/oradata/port/' SCOPE=SPFILE;
--同上，这两个名字转换参数是主备库的路径映射关系，可能会是路径全名，看情况而定
ALTER SYSTEM SET LOG_FILE_NAME_CONVERT='/u01/oracle/oradata/port/','/u01/oracle/oradata/port/' SCOPE=SPFILE;
--一般和LOG_ARCHIVE_DEST_1的位置一样，如果备库采用ARCH传输方式，那么主库会把归档日志传到该目录下
ALTER SYSTEM SET STANDBY_ARCHIVE_DEST='/home/oracle/archivelog/' scope=spfile;
从库的PFILE设置
port.__db_cache_size=1644167168
port.__java_pool_size=167772160
port.__large_pool_size=16777216
port.__shared_pool_size=301989888
port.__streams_pool_size=0
*.audit_file_dest='/home/oracle/admin/port/adump'
*.background_dump_dest='/home/oracle/admin/port/bdump'
*.compatible='10.2.0.4.0'
*.control_files='/u01/oracle/oradata/port/control01.ctl','/u01/oracle/oradata/port/control02.ctl','/u01/oracle/oradata/port/control03.ctl'
*.core_dump_dest='/home/oracle/admin/port/cdump'
*.db_block_size=8192
*.db_domain=''
*.db_file_multiblock_read_count=32
*.db_file_name_convert='/u01/oracle/oradata/port/','/u01/oracle/oradata/port/'
*.db_name='port'
*.db_unique_name='standby'----------------------------这一句漏了，导致默认成了PORT
*.db_recovery_file_dest='/home/oracle/flash_recovery_area'
*.db_recovery_file_dest_size=2147483648
*.dispatchers='(PROTOCOL=TCP) (SERVICE=portXDB)'
*.java_pool_size=157286400
*.job_queue_processes=10
*.log_archive_config='DG_CONFIG=(port,standby)'
*.log_archive_dest_1='LOCATION=/home/oracle/archivelog valid_for=(all_logfiles,all_roles) db_unique_name=standby'
*.log_archive_dest_2='service=port lgwr async valid_for=(online_logfiles,primary_role) db_unique_name=port'
*.log_archive_dest_state_1='ENABLE'
*.log_archive_dest_state_2='ENABLE'
*.log_archive_max_processes=4
*.log_file_name_convert='/u01/oracle/oradata/port/','/u01/oracle/oradata/port/'
*.open_cursors=450
*.pga_aggregate_target=823132160
*.processes=300
*.remote_login_passwordfile='EXCLUSIVE'
*.sga_target=2147483648
*.shared_pool_size=157286400
*.undo_management='AUTO'
*.undo_tablespace='UNDOTBS1'
*.user_dump_dest='/home/oracle/admin/port/udump'
由于db_unique_name成了'port'导致主库和从库无法对应，主库报如下错误：
处理方法：
修改备库参数文件/home/oracle/product/10.2.0/db_1/dbs/initport.ora后
create pfile = '/home/oracle/product/10.2.0/db_1/dbs/initport.ora' from spfile;
然后启动DG
SQL>shutdown immediate;
SQL>startup nomount;
SQL>alter database mount standby database;
SQL>alter database recover managed standby database disconnect from session;
本文转自zylhsy 51CTO博客，原文链接：http://blog.51cto.com/yunlongzheng/775123，如需转载请自行联系原作者
