-------8月在gx行做的，按照行内标准，实现了将原50M每组共5个redolog日志组重建成100M每组共10组。
　　1 查看目前的redolog日志组，得知在用的为group4

SQL> select group#,members,bytes/1024/1024,status from v$log;                                                            
    GROUP#    MEMBERS BYTES/1024/1024 STATUS                
---------- ---------- --------------- ----------------      
         1          2              50 INACTIVE              
         2          2              50 INACTIVE              
         3          2              50 INACTIVE              
         4          2              50 CURRENT                
         5          2              50 INACTIVE          

　　2新增group6-10日志组，大小为100m
alter database add logfile thread 1 group 6('/oradata/CCFICBC/redo06.log','/oradata/CCFICBCredo/redo06b.log') size 100m;                                  
alter database add logfile thread 1 group 7('/oradata/CCFICBC/redo07.log','/oradata/CCFICBCredo/redo07b.log') size 100m;
alter database add logfile thread 1 group 8('/oradata/CCFICBC/redo08.log','/oradata/CCFICBCredo/redo08b.log') size 100m;
alter database add logfile thread 1 group 9('/oradata/CCFICBC/redo09.log','/oradata/CCFICBCredo/redo09b.log') size 100m;
alter database add logfile thread 1 group 10('/oradata/CCFICBC/redo10.log','/oradata/CCFICBCredo/redo10b.log') size 100m;

　　3 drop掉group1235日志组，因为group4在用，所以需要先切换日志组。切完后用查状态语句确认group4不在用，然后再drop .
alter database drop logfile group 1;  
alter database drop logfile group 2;
alter database drop logfile group 3;
alter database drop logfile group 5;
alter system switch logfile;
select group#,members,bytes/1024/1024,status from v$log;
alter database drop logfile group 4;

　　4在操作系统层面上删除日志文件
rm /oradata/CCFICBC/redo01.log  
rm /oradata/CCFICBCredo/redo01b.log
rm /oradata/CCFICBC/redo02.log                      
rm /oradata/CCFICBCredo/redo02b.log
rm /oradata/CCFICBC/redo03.log                      
rm /oradata/CCFICBCredo/redo03b.log
rm /oradata/CCFICBC/redo05.log                      
rm /oradata/CCFICBCredo/redo05b.log
rm /oradata/CCFICBC/redo04.log                      
rm /oradata/CCFICBCredo/redo04b.log
　　5再重新建立group1-5组，大小为100M
alter database add logfile thread 1 group 1('/oradata/CCFICBC/redo01.log','/oradata/CCFICBCredo/redo01b.log') size 100m;
alter database add logfile thread 1 group 2('/oradata/CCFICBC/redo02.log','/oradata/CCFICBCredo/redo02b.log') size 100m;
alter database add logfile thread 1 group 3('/oradata/CCFICBC/redo03.log','/oradata/CCFICBCredo/redo03b.log') size 100m;
alter database add logfile thread 1 group 4('/oradata/CCFICBC/redo04.log','/oradata/CCFICBCredo/redo04b.log') size 100m;
alter database add logfile thread 1 group 5('/oradata/CCFICBC/redo05.log','/oradata/CCFICBCredo/redo05b.log') size 100m;
     
　　6用此语句确认完成
SQL>  select group#,members,bytes/1024/1024,status from v$log;

    GROUP#    MEMBERS BYTES/1024/1024 STATUS
---------- ---------- --------------- ----------------
         1          2             100 CURRENT
         2          2             100 UNUSED
         3          2             100 UNUSED
         4          2             100 UNUSED
         5          2             100 UNUSED
         6          2             100 INACTIVE
         7          2             100 ACTIVE
         8          2             100 UNUSED
         9          2             100 UNUSED
        10          2             100 UNUSED