Redo 非current损坏

   Redo log 文件损坏或丢失，在启动数据库时在alert日志中会有如下错误：

ORA-00313: open failed for members of log group 1 of thread 1

ORA-00312: online log 1 thread 1: '/u01/app/oracle/oradata/orcl/redo01.log'

ORA-27037: unable to obtain file status

Linux-x86_64 Error: 2: No such file or directory

log group 1'/u01/app/oracle/oradata/orcl/redo01.log'丢失，首先确定该日志组状态：

SQL> select group#,sequence#,archived,status from v$log;

    GROUP#  SEQUENCE# ARC STATUS

---------- ---------- --- ----------------

         1          1 YES INACTIVE

         3          3 NO  CURRENT

         2          2 YES INACTIVE

log group 1为非当前联机日志，可以采用如下方法解决：

SQL> alter database clear logfile group 1;     

Database altered.

SQL> alter database open;   

Database altered.

如果该日志组还没有归档，可以使用下面命令强行clear，强行clear后最好作一次数据库的全备份

SQL>alter database clear unarchived logfile group 1;