SQL> select group#,bytes/1024/1024 MB ,status from v$log
2 /
GROUP# MB STATUS
---------- ---------- ----------------
1 10 ACTIVE
2 10 CURRENT
3 10 INACTIVE
SQL> select * from v$logfile;
GROUP# STATUS TYPE MEMBER IS_RECOVERY_DEST_FILE
---------- ------- ------- -------------------------------------------------------------------------------- ---------------------
1 ONLINE /bases/oracle/oradata/CTMMS/redo01.log NO
2 ONLINE /bases/oracle/oradata/CTMMS/redo02.log NO
3 ONLINE /bases/oracle/oradata/CTMMS/redo03.log NO
SQL> alter database add logfile group 4 ('/bases/oracle/oradata/CTMMS/redo04.log') size 512M;
Database altered
SQL> alter database add logfile group 5 ('/bases/oracle/oradata/CTMMS/redo05.log') size 512M;
Database altered
SQL> alter database add logfile group 6 ('/bases/oracle/oradata/CTMMS/redo06.log') size 512M;
Database altered
SQL> select group#,bytes/1024/1024 MB ,status from v$log
2 /
GROUP# MB STATUS
---------- ---------- ----------------
1 10 INACTIVE
2 10 ACTIVE
3 10 INACTIVE
4 512 CURRENT
5 512 UNUSED
6 512 UNUSED
6 rows selected
SQL>
SQL> alter database drop logfile group 1;
Database altered
SQL> select * from v$logfile;
GROUP# STATUS TYPE MEMBER IS_RECOVERY_DEST_FILE
---------- ------- ------- -------------------------------------------------------------------------------- ---------------------
2 ONLINE /bases/oracle/oradata/CTMMS/redo02.log NO
3 ONLINE /bases/oracle/oradata/CTMMS/redo03.log NO
4 ONLINE /bases/oracle/oradata/CTMMS/redo04.log NO
5 ONLINE /bases/oracle/oradata/CTMMS/redo05.log NO
6 ONLINE /bases/oracle/oradata/CTMMS/redo06.log NO
SQL> select group#,bytes/1024/1024 MB ,status from v$log
2 /
GROUP# MB STATUS
---------- ---------- ----------------
2 10 ACTIVE
3 10 INACTIVE
4 512 CURRENT
5 512 UNUSED
6 512 UNUSED
SQL> alter system switch logfile;
System altered
SQL> select group#,bytes/1024/1024 MB ,status from v$log;
GROUP# MB STATUS
---------- ---------- ----------------
2 10 INACTIVE
3 10 INACTIVE
4 512 ACTIVE
5 512 CURRENT
6 512 UNUSED
SQL> alter database drop logfile group 2;
Database altered
SQL> alter database drop logfile group 3;
Database altered