Easy As Pie: Changing REDO Logfile Sizes

Below is a quick and to the point example of how to quickly change you current logfile sizes.  

Log in as sys

Select * from v$log; 
- (The Group# field will tell you what you current highest logfile group number being used is).


Select * from v$controlfile_record_section where type ='REDO LOG';
- (Comparing the Records_Used against the Records_Total will tell you how man more groups can be added).

Alter database add logfile group 5 ''+DGRP_RAID5_01_0000' size 1G reuse;
Alter database add logfile group 6 ''+DGRP_RAID5_01_0000' size 1G reuse;
Alter database add logfile group 7 ''+DGRP_RAID5_01_0000' size 1G reuse;
Alter database add logfile group 8 ''+DGRP_RAID5_01_0000' size 1G reuse;

Or


Alter database add logfile group 5 ''+DGRP_RAID5_01_0000' size 1G reuse
                                                ,''+DGRP_RAID5_01_0000' size 1G reuse;
Alter database add logfile group 6 ''+DGRP_RAID5_01_0000' size 1G reuse
                                                ,''+DGRP_RAID5_01_0000' size 1G reuse;
Alter database add logfile group 7 ''+DGRP_RAID5_01_0000' size 1G reuse
                                                ,''+DGRP_RAID5_01_0000' size 1G reuse;
Alter database add logfile group 8 ''+DGRP_RAID5_01_0000' size 1G reuse
                                               , ''+DGRP_RAID5_01_0000' size 1G reuse;



-(Add your new logfile groups).


Select * from v$log;
-(Use the Status filed to ensure that none of you old logfile groups are "CURRENT").
-(If any of them are, then use the following as many times as necessary to move the "CURRENT" to a new log).


Alter system switch logfile;

Alter system checkpoint;
-(This will force a checkpoint and write all the current contents of the logs to the appropriate data file(s)).



Alter database drop logfile group 1;
Alter database drop logfile group 2;
Alter database drop logfile group 3;
Alter database drop logfile group 3;
-(This will drop the old log file groups).


Select * form v$log;
-(To see your handy work).