修改oracle为归档模式

SQL> archive log list;
Database log mode           No Archive Mode
Automatic archival           Disabled
Archive destination           USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence     16
Current log sequence           18

SQL> archive log list;
Database log mode           No Archive Mode
Automatic archival           Disabled
Archive destination           USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence     16
Current log sequence           18

SQL> startup  mount;
ORACLE instance started.

Total System Global Area 3290345472 bytes
Fixed Size            2217832 bytes
Variable Size         1795164312 bytes
Database Buffers     1476395008 bytes
Redo Buffers           16568320 bytes
Database mounted.

SQL>  alter database archivelog;

Database altered.

SQL> alter database open;

Database altered.

SQL> archive log list;
Database log mode           Archive Mode
Automatic archival           Enabled
Archive destination           USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence     16
Next log sequence to archive   18
Current log sequence           18

SQL> show parameter db_recovery_file_dest;

NAME                     TYPE     VALUE
------------------------------------ ----------- ------------------------------
db_recovery_file_dest             string     /usr/oracle/app/flash_recovery_area
db_recovery_file_dest_size         big integer 3882M