Add a redo log member to an existing redo log group in an Oracle database
SQL> select group#,status,member from v$logfile;
GROUP# STATUS
---------- -------
MEMBER
--------------------------------------------------------------------------------
3
/u01/app/oracle/oradata/DB1/redo03.log
2
/u01/app/oracle/oradata/DB1/redo02.log
1
/u01/app/oracle/oradata/DB1/redo01.log
SQL>
SQL> select group#,members,archived,status from v$log;
GROUP# MEMBERS ARC STATUS
---------- ---------- --- ----------------
1 1 NO CURRENT
2 1 YES INACTIVE
3 1 YES INACTIVE
SQL>
SQL> alter database add logfile member '/u01/app/oracle/oradata/DB1/redo01b.log' to group 1;
Database altered.
SQL> select member from v$logfile;
MEMBER
--------------------------------------------------------------------------------
/u01/app/oracle/oradata/DB1/redo03.log
/u01/app/oracle/oradata/DB1/redo02.log
/u01/app/oracle/oradata/DB1/redo01.log
/u01/app/oracle/oradata/DB1/redo01b.log
SQL>
Best Practices & Notes
Always add members on different disks for redundancy.
The new log file must not exist already on disk.
All members of a group are written to simultaneously — they are identical.
Adding a member does not affect the database availability.