Increase Redo Log Size

# First add new redo groups after checking the current redo logs and groups

SQL> select * from v$log;


    GROUP#    THREAD#  SEQUENCE#      BYTES  BLOCKSIZE    MEMBERS ARC STATUS           FIRST_CHANGE# FIRST_TIM NEXT_CHANGE# NEXT_TIME
---------- ---------- ---------- ---------- ---------- ---------- --- ---------------- ------------- --------- ------------ ---------
         1          1         26 6596591616        512          2 NO  INACTIVE                699445 23-FEB-15       719471 23-FEB-15
         2          1         27 6596591616        512          2 NO  CURRENT                 719471 23-FEB-15   2.8147E+14
         3          1         12 6596591616        512          2 YES INACTIVE                699401 23-FEB-15       699404 23-FEB-15

SQL> select * from v$logfile;

    GROUP# STATUS  TYPE    MEMBER                                             IS_
---------- ------- ------- -------------------------------------------------- ---
         1         ONLINE  /opt/app/dbname/oraredo01/dbname/redo_1a.log   NO
         1         ONLINE  /opt/app/dbname/oraredo02/dbname/redo_1b.log   NO
         2         ONLINE  /opt/app/dbname/oraredo01/dbname/redo_2a.log   NO
         2         ONLINE  /opt/app/dbname/oraredo02/dbname/redo_2b.log   NO
         3         ONLINE  /opt/app/dbname/oraredo01/dbname/redo_3a.log   NO


#### adding new group ; add the same number of groups ie 3 in this case or add more if you want to increase the number of groups
alter database add logfile group 4 ('/opt/app/dbname/oraredo01/dbname/redo_4a.log','/opt/app/dbname/oraredo02/dbname/redo_4b.log') size 2048m reuse;
alter database add logfile group 5 ('/opt/app/dbname/oraredo01/dbname/redo_5a.log','/opt/app/dbname/oraredo02/dbname/redo_5b.log') size 2048m reuse;
alter database add logfile group 6 ('/opt/app/dbname/oraredo01/dbname/redo_6a.log','/opt/app/dbname/oraredo02/dbname/redo_6b.log') size 2048m reuse;
alter database add logfile group 7 ('/opt/app/dbname/oraredo01/dbname/redo_7a.log','/opt/app/dbname/oraredo02/dbname/redo_7b.log') size 2048m reuse;

##Make the new redo log CURRENT

SQL> select group#, status from v$log;

    GROUP# STATUS
---------- ----------------
         1 INACTIVE
         2 CURRENT
         3 INACTIVE
         4 UNUSED
         5 UNUSED
         6 UNUSED
         7 UNUSED
SQL> alter system switch logfile;

System altered.

SQL> alter system switch logfile;

System altered.

SQL> select group#, status from v$log;

    GROUP# STATUS
---------- ----------------
         1 INACTIVE
         2 ACTIVE
         3 INACTIVE
         4 ACTIVE
         5 CURRENT
         6 UNUSED
         7 UNUSED

7 rows selected.

#Drop old redo logs ; Make sure their status is inactive before dropping it.
SQL> alter database drop logfile group 1;
SQL> alter database drop logfile group 2;
SQL> alter database drop logfile group 3;

## make some logswitches to make all the redo logs used.