方法一：
调整ORACLE日志文件为8个
默认下，oracle日志为3个，可以调整为8个以避免日志文件
1、创建5个新的日志组
ALTER DATABASE ADD LOGFILE GROUP 4 ('/u01/app/oracle/oradata/orcl/redo04.log') SIZE 50M;
ALTER DATABASE ADD LOGFILE GROUP 5 ('/u01/app/oracle/oradata/orcl/redo05.log') SIZE 50M;
ALTER DATABASE ADD LOGFILE GROUP 6 ('/u01/app/oracle/oradata/orcl/redo06.log') SIZE 50M;
ALTER DATABASE ADD LOGFILE GROUP 7 ('/u01/app/oracle/oradata/orcl/redo07.log') SIZE 50M;
ALTER DATABASE ADD LOGFILE GROUP 8 ('/u01/app/oracle/oradata/orcl/redo08.log') SIZE 50M;
2、切换当前日志到新的日志组
alter system switch logfile;
alter system switch logfile;
alter system switch logfile;
alter system switch logfile;
alter system switch logfile;
3、查看每组状态的命令为：
select group#,sequence#,archived,members,status from v$log;
方法二：
方法二：
1.创建3个新的日志组
sql> ALTER DATABASE ADD LOGFILE GROUP 4 ('/u01/app/oracle/oradata/orcl/redo04.log') SIZE 500M;
sql> ALTER DATABASE ADD LOGFILE GROUP 5 ('/u01/app/oracle/oradata/orcl/redo05.log') SIZE 500M;
sql> ALTER DATABASE ADD LOGFILE GROUP 6 ('/u01/app/oracle/oradata/orcl/redo06.log') SIZE 500M;
查看日志组
sql> select * from v$logfile;
2.切换当前日志到新的日志组
sql> alter system switch logfile;
sql> alter system switch logfile;
sql> alter system switch logfile;
要删除为INCACTIVE状态才行
sql> select group#,bytes,status from v$log;
GROUP# SEQUENCE# BYTES MEMBERS STATUS
---------- ---------- ---------- ---------- ----------------
1 139 52428800 1 INACTIVE
2 137 52428800 1 INACTIVE
3 138 52428800 1 INACTIVE
4 140 524288000 1 ACTIVE
5 141 524288000 1 CURRENT
6 136 524288000 1 INACTIVE
3.删除旧的日志组
sql> alter database drop logfile group 1;
Database altered.
sql> alter database drop logfile group 2;
Database altered.
sql> alter database drop logfile group 3;
查看是否删除了日志组
sql> select group#,status from v$log;
GROUP# SEQUENCE# BYTES MEMBERS STATUS
---------- ---------- ---------- ---------- ----------------
4 140 524288000 1 INACTIVE
5 141 524288000 1 CURRENT
6 136 524288000 1 INACTIVE
[oracle@oracle122 log]$ cd /u01/app/oracle/oradata/orcl
[oracle@oracle122 orcl]$
[oracle@oracle122 orcl]$ pwd
/u01/app/oracle/oradata/orcl
[oracle@oracle122 orcl]$ ls
control01.ctl example01.dbf redo01.log redo02.log redo03.log redo04.log redo05.log redo06.log sysaux01.dbf system01.dbf temp01.dbf undotbs01.dbf users01.dbf
[oracle@oracle122 orcl]$ rm -rf redo01.log
[oracle@oracle122 orcl]$ rm -rf redo02.log
[oracle@oracle122 orcl]$ rm -rf redo03.log
5.重建日志组1、2、3
sql> ALTER DATABASE ADD LOGFILE GROUP 1 ('/u01/app/oracle/oradata/orcl/redo01.log') SIZE 500M;
sql> ALTER DATABASE ADD LOGFILE GROUP 2 ('/u01/app/oracle/oradata/orcl/redo02.log') SIZE 500M;
sql> ALTER DATABASE ADD LOGFILE GROUP 3 ('/u01/app/oracle/oradata/orcl/redo03.log') SIZE 500M;
7.删除中间过渡用的日志组4、5、6 ，在删除时查询select group#,status from v$log; 删除组是否为INACTIVE，如果不是INACTIVE 就要执行alter system switch logfile;
查询看一下
sql> select group#,status from v$log;
GROUP# SEQUENCE# BYTES MEMBERS STATUS
---------- ---------- ---------- ---------- ----------------
1 148 524288000 1 CURRENT
2 143 524288000 1 INACTIVE
3 144 524288000 1 INACTIVE
4 146 524288000 1 INACTIVE
5 147 524288000 1 INACTIVE
6 145 524288000 1 INACTIVE
sql> alter database drop logfile group 4;
Database altered.
sql> alter database drop logfile group 5;
Database altered.
sql> alter database drop logfile group 6;
Database altered.
8.到操作系统删除组4、5、6
[oracle@oracle122 orcl]$ rm -rf redo04.log
[oracle@oracle122 orcl]$ rm -rf redo05.log
[oracle@oracle122 orcl]$ rm -rf redo06.log
9.备份当前最新的控制文件
sql> alter database backup controlfile to trace resetlogs ;
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