1。若数据库为非归档模式，则数据不能保持它的完整。
1。su - oracle
1.1. modify the /opt/oracle/admin/dbora817/pfile/initdbora817.ora,make sure that
log_archive_start = true
log_archive_dest_1 = "location=/opt/oracle/admin/dbora817/arch"
log_archive_format = arch_%t_%s.arc
are not commented.
2. sqlplus '/ as sysdba'
3. SQL>shutdown
SQL>startup mount
SQL>alter database archivelog;
SQL>alter database open;
4. verify:
SQL>archive log list
Database log mode Archive Mode
Automatic archival ENABLED
Archive destination /opt/oracle/admin/dbora817/arch
Oldest online log sequence 19
Next log sequence to archive 21
Current log sequence 21
