#mkdir /oradata/flash_recovery_area

SQL>startup mount

SQL>alter system set db_recovery_file_dest_size = 30G;

SQL>alter system set db_recovery_file_dest = '/oradata/flash_recovery_area';

根据需要创建spfile，如果没创建，系统会报错

SQL>create spfile from pfile

SQL>shutdown immediate

SQL>sqlplus / as sysdba

SQL>startup mount

如不需创建spfile，则直接执行下面语句

[@more@]

SQL>alter system set log_archive_format = '%t_%s_%r.arc' scope=spfile;

SQL>alter system set log_archive_dest_10 = 'LOCATION=USE_DB_RECOVERY_FILE_DEST OPTIONAL REOPEN=300';

SQL>shutdown immediate

SQL>startup mount

SQL>alter database archivelog;

SQL>alter database open;

SQL>alter system switch logfile;

开启后，可使用如下语句查看

SQL>archive log list

SQL>show parameter db_recovery

ITPub博客

一例：oracle开启归档日志