Oracle redo logfile 调整 - 修改路径， 改变大小，增大

1. check current acive one
select group#, status from v$log;
select * from v$logfile;

2. create two new logfiles with new size
alter database add logfile group 4('/ptc/Windchill_11.0/ocu/oradata/wind/windredo04.log') size 100m;
alter database add logfile group 5('/ptc/Windchill_11.0/ocu/oradata/wind/windredo05.log') size 100m;

3. switch to current new logfiles
alter system switch logfile;
alter system switch logfile;

4. drop old log files.
alter database drop logfile group 1;
alter database drop logfile group 2;
alter database drop logfile group 3;

5. delete old three physicial files, and create three old logfiles with new size
alter database add logfile group 1('/ptc/Windchill_11.0/ocu/oradata/wind/windredo01.log') size 100m;
alter database add logfile group 2('/ptc/Windchill_11.0/ocu/oradata/wind/windredo02.log') size 100m;
alter database add logfile group 3('/ptc/Windchill_11.0/ocu/oradata/wind/windredo03.log') size 100m;

6. delete the two new log files, and delete files
alter database drop logfile group 4;
alter database drop logfile group 5;