1. 非归档模式下，非current redo 丢失或损坏(inactive状态）
方法：直接清除损坏日志组，或者直接删除日志，打开数据库后再重新添加；
注意：归档模式方法一样
--例子
--Session 1
SQL> select * from v$log;
GROUP# THREAD# SEQUENCE# BYTES BLOCKSIZE MEMBERS ARC STATUS FIRST_CHANGE# FIRST_TIM NEXT_CHANGE# NEXT_TIME
---------- ---------- ---------- ---------- ---------- ---------- --- ---------------- --------------------------
1 1 91 52428800 512 1 NO CURRENT 1627245 29-DEC-15 2.8147E+14
2 1 89 52428800 512 1 NO INACTIVE 1627239 29-DEC-15 1627242 29-DEC-15
3 1 90 52428800 512 1 NO INACTIVE 1627242 29-DEC-15 1627245 29-DEC-15
SQL> col member for a70
SQL> select * from v$Logfile;
GROUP# STATUS TYPE MEMBER IS_
---------- ------- ------- -------------------------------------
1 ONLINE /u01/app/oracle/oradata/orcl/redo01.log NO
2 ONLINE /u01/app/oracle/oradata/orcl/redo02.log NO
3 ONLINE /u01/app/oracle/oradata/orcl/redo03.log NO
SQL> alter system checkpoint;
System altered.
--Session 2 把group3的inactive状态的redo损坏
[root@zw_test_26_75 ~]# dd if=/dev/null of=/u01/app/oracle/oradata/orcl/redo03.log bs=512 count=10
0+0 records in
0+0 records out
0 bytes (0 B) copied, 0.000115041 s, 0.0 kB/s
--Session 1
SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
数据库能不能正常起来？
这个是非归档
SQL> startup
ORACLE instance started.
Total System Global Area 952020992 bytes
Fixed Size 2258960 bytes
Variable Size 314574832 bytes
Database Buffers 629145600 bytes
Redo Buffers 6041600 bytes
Database mounted.
ORA-03113: end-of-file on communication channel
Process ID: 14561
Session ID: 145 Serial number: 3
启动报错，查看alert.log日志
Errors in file /u01/app/oracle/diag/rdbms/orcl/orcl/trace/orcl_lgwr_14545.trc:
ORA-00313: open failed for members of log group 3 of thread 1
ORA-00312: online log 3 thread 1: '/u01/app/oracle/oradata/orcl/redo03.log'
ORA-27047: unable to read the header block of file
怎么顺利打开数据库?
SQL> alter database clear logfile group 3;
Database altered.
能不能打开数据库
SQL> alter database open;
Database altered.
SQL> select status from v$instance;
STATUS
------------
OPEN
数据库已经打开,如果此时打开报错，就用以下方法尝试；
SQL> alter database drop logfile group 2;
Database altered.
SQL> alter database open;
Database altered.
SQL> alter database add logfile group 2 ('/u01/app/oracle/oradata/orcl/redo02.log') size 20m;
Database altered.
