Offline Method
1. Shut down the database.
2. Copy the online redo log files to the new location. Operating system files, such as online redo log members, must be copied using the appropriate operating system commands.
The following example uses operating system commands (UNIX) to move the online redo log members to a new location:
$ mv /diska/logs/log1a.rdo /diskc/logs/log1c.rdo $ mv /diska/logs/log2a.rdo /diskc/logs/log2c.rdo
3. Startup the database in mount mode, but do not open it.
SQL> CONNECT / as SYSDBA SQL> STARTUP MOUNT
4. Rename the online redo log members.
SQL> ALTER DATABASE RENAME FILE '/diska/logs/log1a.rdo', '/diska/logs/log2a.rdo' TO '/diskc/logs/log1c.rdo', '/diskc/logs/log2c.rdo';
5. Open the database for normal operation.
SQL> ALTER DATABASE OPEN;
Online Method
If the database cannot be shut down, it will not possible to rename the files directly. In this case, first add new groups and then drop the non-needed ones.
1. Add as many new groups as the ones to be renamed with the following commands:
SQL> ALTER DATABASE ADD LOGFILE group 4 ('/log01A.dbf', '/log01B.dbf ') SIZE 512M;
SQL> ALTER DATABASE ADD LOGFILE group 5 ('/log02A.dbf', '/log02B.dbf ') SIZE 512M;
SQL> ALTER DATABASE ADD LOGFILE group 6 ('/log03A.dbf', '/log03B.dbf ') SIZE 512M;
2. Then drop the online redo log groups that are not needed anymore: you must have the ALTER DATABASE system privilege. Before dropping an online redo log group, consider the following restrictions and precautions:
– An instance requires at least two groups of online redo log files, regardless of the number of members in the groups. (A group is one or more members.)
– You can drop an online redo log group only if it is INACTIVE. If you need to drop the current group, first force a log switch to occur.
Make sure an online redo log group is archived (if archiving is enabled) before dropping it.
To see whether this has happened, use the V$LOG view :
SQL> SELECT GROUP#, ARCHIVED, STATUS FROM V$LOG; GROUP# ARC STATUS --------- --- ---------------- 1 YES ACTIVE 2 NO CURRENT 3 YES INACTIVE 4 YES UNUSED 5 YES UNUSED 6 YES UNUSED
As group 3 is in INACTIVE mode, you can drop it :
SQL> ALTER DATABASE DROP LOGFILE GROUP 3;
3. After dropping an online redo log group, make sure that the drop completed successfully, and then use the appropriate operating system command to delete the dropped online redo log files.