SAP ORACLE LOG FILE SWITCHING!!!!!!!!!!!!!!! INCREASE LOG FILE SIZE TO 150MB

 For the optimum performance you can increase the size of redo log filze size up to 150 MB , here I am going to discribe  online redo log migration from 50 MB to 150MB.

The Redo Logs must be dropped and recreated for changing the redo log size. It can be done online without shutting down the database. However, you need to make sure that the Redo Group being dropped should be INACTIVE when you do this.

Check Redo Log group and Status:
SQL> Select group#, status from v$log;
    GROUP# STATUS
---------- ----------------
         1 ACTIVE
         2 ACTIVE
         3 CURRENT

         4 ACTIVE
SQL> select group#,members,status,bytes/1024/1024 as mb from v$log;

    GROUP#    MEMBERS STATUS       MB
---------- ---------- ---------------- ----------
         1          2 ACTIVE                          50
         2          2 ACTIVE                         50
         3          2 CURRENT                     50
         4          2 ACTIVE                         50

Check the log file locationm group, and status

SQL>select * from v$logfile;

Group     Status                 Location
4 ONLINE E:\ORACLE\GEP\ORIGLOGB\LOG_G14M1.DBF
4 ONLINE F:\ORACLE\GEP\MIRRLOGB\LOG_G14M2.DBF
3 ONLINE E:\ORACLE\GEP\ORIGLOGA\LOG_G13M1.DBF
3 ONLINE F:\ORACLE\GEP\MIRRLOGA\LOG_G13M2.DBF
2 ONLINE E:\ORACLE\GEP\ORIGLOGB\LOG_G12M1.DBF
2 ONLINE F:\ORACLE\GEP\MIRRLOGB\LOG_G12M2.DBF
1 ONLINE E:\ORACLE\GEP\ORIGLOGA\LOG_G11M1.DBF

1 ONLINE F:\ORACLE\GEP\MIRRLOGA\LOG_G11M2.DBF


#--SQL> select group#,members,status,bytes/1024/1024 as mb from v$log;


    GROUP#    MEMBERS STATUS                   MB
---------- ---------- ---------------- ----------
         1          2 INACTIVE                150
         2          2 INACTIVE                150
         3          2 CURRENT                 150
         4          2 ACTIVE                   50
         5          2 INACTIVE                150
         6          2 INACTIVE                150
         7          4 INACTIVE                150

#--7 rows selected.

alter system checkpoint;

ALTER SYSTEM CHECKPOINT GLOBAL;

SQL> ALTER SYSTEM CHECKPOINT GLOBAL;

System altered.

--SQL> select group#,members,status,bytes/1024/1024 as mb from v$log;

    GROUP#    MEMBERS STATUS                   MB
---------- ---------- ---------------- ----------
         1          2 INACTIVE                150
         2          2 INACTIVE                150
         3          2 CURRENT                 150
         4          2 INACTIVE                 50
         5          2 INACTIVE                150
         6          2 INACTIVE                150
         7          4 INACTIVE                150

--7 rows selected.




 alter system switch logfile;


ALTER DATABASE DROP LOGFILE GROUP 1;

alter database ADD  logfile GROUP 1 ('F:\ORACLE\GEP\MIRRLOGB\LOG150N_G14M2.DBF','F:\ORACLE\GEP\MIRRLOGB\LOG150N_G12M2.DBF') SIZE 150M REUSE

alter system switch logfile;


ALTER DATABASE DROP LOGFILE GROUP 2;


alter database ADD  logfile GROUP 2 ('F:\ORACLE\GEP\MIRRLOGB\LOG150N_G11M2.DBF','E:\ORACLE\GEP\ORIGLOGB\LOG150N_G12M1.DBF') SIZE 150M REUSE;

alter system switch logfile;


ALTER DATABASE DROP LOGFILE GROUP 3;


alter database ADD  logfile GROUP 3 ('E:\ORACLE\GEP\ORIGLOGA\LOG150N_G13M1.DBF','F:\ORACLE\GEP\MIRRLOGA\LOG150N_G13M2.DBF') SIZE 150M REUSE;

alter system switch logfile;


ALTER DATABASE DROP LOGFILE GROUP 4;


alter database ADD  logfile GROUP 4 ('E:\ORACLE\GEP\ORIGLOGB\LOG150N_G14M1.DBF','F:\ORACLE\GEP\MIRRLOGB\LOG150N_G11M1.DBF') SIZE 150M REUSE;


alter system switch logfile;


Complete!

refer this: https://muneer2908.wordpress.com/2011/01/27/how-to-change-the-redo-log-file-size-in-oracle-database/