模拟服务器突然掉电，数据库丢失，事务无法完成回滚故障的恢复
数据库的状态如下：
SQL> select instance_name,status from v$instance;
INSTANCE_NAME STATUS
---------------- ------------
marven OPEN
非归档模式：
SQL> archive log list
Database log mode No Archive Mode
Automatic archival Disabled
Archive destination /u01/app/Oracle/product/10.2.0/db_1/dbs/arch
Oldest online log sequence 25
Current log sequence 27
SQL> set linesize 150 pagesize 300
SQL> select * from v$log;
GROUP# THREAD# SEQUENCE# BYTES MEMBERS ARC STATUS FIRST_CHANGE# FIRST_TIM
---------- ---------- ---------- ---------- ---------- --- ---------------- ------------- ---------
1 1 25 52428800 1 NO CURRENT 384492 29-JAN-12
2 1 23 52428800 1 NO INACTIVE 371795 29-JAN-12
3 1 24 52428800 1 NO INACTIVE 377698 29-JAN-12
采用shutdown abort模拟突然掉电，数据库关闭的情形，此时数据库可以正常启动到MOUNT状态
SQL> shutdown abort
ORACLE instance shut down.
SQL> startup mount
ORACLE instance started.
Total System Global Area 1610612736 bytes
Fixed Size 2084296 bytes
Variable Size 385876536 bytes
Database Buffers 1207959552 bytes
Redo Buffers 14692352 bytes
Database mounted.
此时日志状态如下：
SQL> select * from v$log;
GROUP# THREAD# SEQUENCE# BYTES MEMBERS ARC STATUS FIRST_CHANGE# FIRST_TIM
---------- ---------- ---------- ---------- ---------- --- ---------------- ------------- ---------
1 1 25 52428800 1 NO ACTIVE 384492 29-JAN-12
3 1 27 52428800 1 NO CURRENT 391086 29-JAN-12
2 1 26 52428800 1 NO ACTIVE 389733 29-JAN-12
删除所有的重做日志文件：
SQL>!rm /u01/app/oracle/oradata/marven/redo*.log
SQL> shutdown abort
ORACLE instance shut down.
SQL>startup nomount
Total System Global Area 1610612736 bytes
Fixed Size 2084296 bytes
Variable Size 385876536 bytes
Database Buffers 1207959552 bytes
Redo Buffers 14692352 bytes
SQL> alter database mount;
Database altered.
在打开数据库时发现无法正常打开
SQL> alter database open;
alter database open
*
ERROR at line 1:
ORA-00313: open failed for members of log group 1 of thread 1
ORA-00312: online log 1 thread 1: '/u01/app/oracle/oradata/marven/redo01.log'
ORA-27037: unable to obtain file status
Linux-x86_64 Error: 2: No such file or directory
Additional information: 3
试图通过resetlog打开数据库发现是行不通的：
SQL> alter database open resetlogs;
alter database open resetlogs
*
ERROR at line 1:
ORA-01139: RESETLOGS option only valid after an incomplete database recovery
spfile参数文件的目录如下：
SQL> show parameter spfile;
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
spfile string /u01/app/oracle/product/10.2.0
/db_1/dbs/spfilemarven.ora