修改redo_logfile組成員和大小

1.SYS@ORCL>select GROUP#  ,BYTES/1024/1024 size_M,STATUS,ARCHIVED from v$log;

    GROUP#    SIZE_M STATUS          ARC                                     
 ---------- ---------- ---------------- ---                                     
          1        50 INACTIVE        YES                                     
          2        50 INACTIVE        YES                                     
          3        50 CURRENT          NO          

2.刪除原有的日志組；（只操作狀態(tài)為inactive的日志組）
  若要操作日志組為current時(shí)，需先進(jìn)行日志切換：alter system switch logfile;
  若為active時(shí)，則可強(qiáng)制進(jìn)行檢查點(diǎn)：alter system checkpoint;

SYS@ORCL>alter system switch logfile;

System altered.

SYS@ORCL>alter system checkpoint; --強(qiáng)制執(zhí)行檢查點(diǎn)

SYS@ORCL>select GROUP#  ,BYTES/1024/1024 size_M,STATUS,ARCHIVED from v$log;

    GROUP#    SIZE_M STATUS          ARC                                     
 ---------- ---------- ---------------- ---                                     
          1        50 INACTIVE        YES                                     
          2        50 INACTIVE        YES                                     
          3        50 ACTIVE          YES    

SYS@ORCL>alter database drop logfile group 1;

Database altered.

SYS@ORCL>alter database drop logfile group 2;

Database altered.
                                

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刪除后還需要去指定目錄刪除日志文件，后才能建立文件，如制定別的名字的日志組，應(yīng)該沒有此限制。
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3.添加3組大小為200M的日志組；
SYS@ORCL>alter database add logfile group 1 '/u01/app/oracle/oradata/orcl11g/redo01.log'size 200m;

Database altered.

SYS@ORCL>alter database add logfile group 2 '/u01/app/oracle/oradata/orcl11g/redo02.log'size 200m;

Database altered.

SYS@ORCL>alter database add logfile group 3 '/u01/app/oracle/oradata/orcl11g/redo03.log'size 200m;

4.給日志組添加成員
cd  /u01/app/oracle/oradata/orcl11g/
mkdir redo_bak

SYS@ORCL>alter database add logfile member '/u01/app/oracle/oradata/orcl11g/redo_bak/redo01_b.log' to group 1;
Database altered.
SYS@ORCL>alter database add logfile member '/u01/app/oracle/oradata/orcl11g/redo_bak/redo02_b.log' to group 2;
Database altered.
SYS@ORCL>alter database add logfile member '/u01/app/oracle/oradata/orcl11g/redo_bak/redo03_b.log' to group 3;
Database altered.

5.刪除日志組成員

alter database drop logfile member '/u01/app/oracle/oradata/orcl11g/redo_bak/redo02_b.log';