归档日志路径三个参数DB_RECOVERY_FILE_DEST和LOG_ARCHIVE_DEST和LOG_ARCHIVE_DEST_n

LOG_ARCHIVE_DEST_n：默认值为’’。Oracle最多支持把日志文件归档到10个地方，n从1到10。归档地址可以为本地磁盘，或者网络设备。

DB_RECOVERY_FILE_DEST：指定闪回恢复区路径。

三者关系：

1、 如果设置了DB_RECOVERY_FILE_DEST，就不能设置LOG_ARCHIVE_DEST，默认的归档日志存放于DB_RECOVERY_FILE_DEST指定的闪回恢复区中。可以设置LOG_ARCHIVE_DEST_n，如果这样，那么归档日志不再存放于DB_RECOVERY_FILE_DEST中，而是存放于LOG_ARCHIVE_DEST_n设置的目录中。如果想要归档日志继续存放在DB_RECOVERY_FILE_DEST中，可以通过如下命令：alter system set log_archive_dest_1=’location=USE_DB_RECOVERY_FILE_DEST’;

2、 如果设置了LOG_ARCHIVE_DEST，就不能设置LOG_ARCHIVE_DEST_n和DB_RECOVERY_FILE_DEST。如果设置了LOG_ARCHIVE_DEST_n，就不能设置LOG_ARCHIVE_DEST。也就是说，LOG_ARCHIVE_DEST参数和DB_RECOVERY_FILE_DEST、LOG_ARCHIVE_DEST_n都不共存。而DB_RECOVERY_FILE_DEST和LOG_ARCHIVE_DEST_n可以共存。

3、 LOG_ARCHIVE_DEST只能与LOG_ARCHIVE_DUPLEX_DEST共存。这样可以设置两个归档路径。LOG_ARCHIVE_DEST设置一个主归档路径，LOG_ARCHIVE_DUPLEX_DEST设置一个从归档路径。所有归档路径必须是本地的。

4、 如果LOG_ARCHIVE_DEST_n设置的路径不正确，那么Oracle会在设置的上一级目录归档。比如设置LOG_ARCHIVE_DEST_1=’location=C:archive1’，而OS中并没有archive1这个目录，那么Oracle会在C盘归档。

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测试：

SYS@ tsid > show parameter db_recovery_file_dest

NAME                      TYPE       VALUE

--------------------- ---------- ------------------------------

db_recovery_file_dest string     E:oracleproduct10.2.0flash

                                                _recovery_area

SYS@ tsid > alter system set log_archive_dest='e:archive';

alter system set log_archive_dest='e:archive'

*

ERROR at line 1:

ORA-02097: parameter cannot be modified because specified value is invalid

ORA-16018: cannot use LOG_ARCHIVE_DEST with LOG_ARCHIVE_DEST_n or DB_RECOVERY_FILE_DEST

SYS@ tsid > alter system set db_recovery_file_dest='';

System altered.

SYS@ tsid > alter system set log_archive_dest='e:archive';

System altered.

SYS@ tsid > alter system set log_archive_dest_1='e:archive1';

alter system set log_archive_dest_1='e:archive1'

*

ERROR at line 1:

ORA-32017: failure in updating SPFILE

ORA-16179: incremental changes to "log_archive_dest_1" not allowed with SPFILE

SYS@ tsid > alter system set db_recovery_file_dest='E:oracleproduct10.2.0flash_recovery_area';

alter system set db_recovery_file_dest='E:oracleproduct10.2.0flash_recovery_area'

*

ERROR at line 1:

ORA-02097: parameter cannot be modified because specified value is invalid

ORA-16019: cannot use db_recovery_file_dest with LOG_ARCHIVE_DEST or LOG_ARCHIVE_DUPLEX_DEST

SYS@ tsid > alter system set log_archive_dest='';

System altered.

SYS@ tsid > alter system set db_recovery_file_dest='E:oracleproduct10.2.0flash_recovery_area';

System altered.

SYS@ tsid > alter system set log_archive_dest_1='location=e:archive1';

System altered.

SYS@ tsid > alter system switch logfile;

System altered.

E盘中没有archive1目录，直接在E盘下生成了归档日志文件，验证了上面第4点。

SYS@ tsid > alter system set log_archive_dest_1='';

System altered.