在数据库安装时可以选择归档模式，也可以在数据库安装完成后切换成归档模式。模式的切换只能在mount状态下执行，如果在open状态下执行，则会报如下的错误：

sql> alter database noarchivelog;

alter database noarchivelog

*

ERROR at line 1:

ORA-01126: database must be mounted in this instance and not open in any

instance

如果在nomount状态下执行，则会报如下错误：

sql> alter database noarchivelog;

alter database noarchivelog

*

ERROR at line 1:

ORA-01507: database not mounted

归档切换到非归档

在数据库mount阶段执行alter database noarchivelog;

sql> archive log list;

Database log mode Archive Mode#原先为归档模式

Automatic archival Enabled

Archive destination USE_DB_RECOVERY_FILE_DEST #归档文件存放的位置

Oldest online log sequence 129

Next log sequence to archive 131

Current log sequence 131

sql> shutdown immediate;

Database closed.

Database dismounted.

ORACLE instance shut down.

sql> startup mount;

ORACLE instance started.

Total System Global Area 776646656 bytes

Fixed Size 2217384 bytes

Variable Size 482347608 bytes

Database Buffers 289406976 bytes

Redo Buffers 2674688 bytes

Database mounted.

sql> alter database noarchivelog;

Database altered.

sql> alter database open;

Database altered.

sql> archive log list;

Database log mode No Archive Mode

Automatic archival Disabled

Archive destination USE_DB_RECOVERY_FILE_DEST

Oldest online log sequence 129

Current log sequence 131

非归档切换到归档

1、继续面的例子，当前数据库处于非归档模式，如果直接修改成归档模式，那么归档日志存放的位置为DB_RECOVERY_FILE_DEST。

sql> show parameter db_recovery

NAME TYPE VALUE

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

db_recovery_file_dest string /u01/app/oracle/flash_recovery_area

db_recovery_file_dest_size big integer 3882M

闪回恢复区只有3882M的空间，如果不满足需要，可以修改归档的位置。

sql> alter system set log_archive_dest_1="location=/u01/app/oracle/archive";

2、关闭数据库，然后启动到mount状态

sql> shutdown immediate;

sql> startup mount;

sql> alter database archivelog;

sql> alter database open;

sql> archive log list;

Database log mode Archive Mode

Automatic archival Enabled

Archive destination /u01/app/oracle/archive

Oldest online log sequence 129

Next log sequence to archive 131

Current log sequence 131