開歸檔報錯：ora-00265：

SQL> alter database archivelog;
alter database archivelog
*
ERROR at line 1:
ORA-00265: instance recovery required, cannot set ARCHIVELOG mode

上網查了下，原來是上次系統的非正常關閉導致。需要重新開啟資料庫，使資料檔案，控制檔案，日誌檔案同步，再修改歸檔模式。

SQL> alter database open;
Database altered.
SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup mount
ORACLE instance started.
Total System Global Area  419430400 bytes
Fixed Size                  1219760 bytes
Variable Size             121635664 bytes
Database Buffers          293601280 bytes
Redo Buffers                2973696 bytes
Database mounted.
SQL> alter database archivelog;
Database altered.
SQL> alter database open;
Database altered.