【练习---日志恢复】正常关库删除一组当前日志组

1.查询当前日志组及状态：

10:45:14 SYS@ORA11GR2>select group#,member from v$logfile;

    GROUP# MEMBER
---------- --------------------------------------------------
         3 /u01/app/oracle/oradata/ORA11GR2/redo03.log
         2 /u01/app/oracle/oradata/ORA11GR2/redo02.log
         1 /u01/app/oracle/oradata/ORA11GR2/redo01.log
         3 /u01/app/oracle/disk/redo03b.log
         2 /u01/app/oracle/disk/redo02b.log
         1 /u01/app/oracle/disk/redo01b.log

6 rows selected.

10:45:26 SYS@ORA11GR2>select group#,members,bytes/1024/1024 M,status from v$log;

    GROUP#    MEMBERS          M STATUS
---------- ---------- ---------- ----------------
         1          2         50 CURRENT
         2          2         50 INACTIVE
         3          2         50 ACTIVE

2.模拟故障（正常关库删除一组当前日志组）：

10:45:53 SYS@ORA11GR2>shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.

[oracle@host03 ~]$ rm /u01/app/oracle/oradata/ORA11GR2/redo01.log
[oracle@host03 ~]$ rm /u01/app/oracle/disk/redo01b.log

3.起库报错，查看alert日志：

ORA-00313: open failed for members of log group 1 of thread 1
ORA-00312: online log 1 thread 1: '/u01/app/oracle/disk/redo01b.log'
ORA-27037: unable to obtain file status
Linux-x86_64 Error: 2: No such file or directory
Additional information: 3
ORA-00312: online log 1 thread 1: '/u01/app/oracle/oradata/ORA11GR2/redo01.log'
ORA-27037: unable to obtain file status
Linux-x86_64 Error: 2: No such file or directory
Additional information: 3

4.解决：将数据库起到mount

10:50:09 SYS@ORA11GR2>alter database clear logfile group 1;

Database altered.

 
10:51:35 SYS@ORA11GR2>select group#,members,bytes/1024/1024 M,status from v$log;

    GROUP#    MEMBERS          M STATUS
---------- ---------- ---------- ----------------
         1          2         50 UNUSED
         3          2         50 INACTIVE
         2          2         50 CURRENT

10:51:41 SYS@ORA11GR2>alter database open;

Database altered.