Re: Unable to resize Oracle Redo Log online

Hi Carlos,

You need to follow the below method of doing it manually. SAP recommends to resize the online redolog file manually. Its a online activity but i will prefer to do it offline as this might corrupt the database.

Kindly follow the below method.

1. Full backup of the database.

2. Check the existing log files.

select group#, member from v$logfile;

GROUP#    MEMBERS

----------    -----------

1               <driver>:\ORACLE\ORADATA\ORADB\REDO01_1.LOG

2               <driver>:\ORACLE\ORADATA\ORADB\REDO02_1.LOG

3               <driver>:\ORACLE\ORADATA\ORADB\REDO03_1.LOG

3. Add at least two additional log files with proper group number - e.g. group 4 and group 5.

alter database add logfile group 4 ('<driver>:\ORACLE\ORADATA\ORADB\REDO04_1.LOG') size 100MB;

alter database add logfile group 5 ('<driver>:\ORACLE\ORADATA\ORADB\REDO05_1.LOG') size 100MB;

4. Check the current status of logfile by command

select GROUP#, STATUS from v$log;

and make sure the status of the logfile you want to drop later is [INACTIVE].

You need then perform logswitch several times by command [alter system switch logfile;],

until you can drop the required redologs.

5. Drop the original log files.

alter database drop logfile group 1;

alter database drop logfile group 2;

alter database drop logfile group 3;

6. Create the dropped log files with new size.

alter database

add logfile group 1 ('<driver>:\ORACLE\ORADATA\ORADB\REDO01_1.LOG') size 150M;

alter database

add logfile group 2 ('<driver>:\ORACLE\ORADATA\ORADB\REDO02_1.LOG') size 150M;

alter database

add logfile group 3 ('<driver>:\ORACLE\ORADATA\ORADB\REDO03_1.LOG') size 150M;

7. Check and perform logswitch as step 4 above.

8. Drop the additional log files.

alter database drop logfile group 4;

alter database drop logfile group 5;

9. Delete the OS files of additional log files.

<driver>:\ORACLE\ORADATA\ORADB\REDO04_1.LOG

<driver>:\ORACLE\ORADATA\ORADB\REDO05_1.LOG

10. Backup control file.

alter database backup controlfile to trace resetlogs;

11. Check the result.

select group#, members, status, bytes/1024/1024 MB from v$log;

Kindly check the below sapnotes

1961509 - How to manually modify size of ONLINE redo log files

With Regards

Ashutosh Chaturvedi