Method for changing Redo logfile size on online status

If there is 3 small Redo Log file, the following is an example in the UNIX environment:

Step 1: Add three big Redo logfiles to the database

SVRMGRL> ALTER DATABASE Add Logfile Group 4

('/opt/oradata/app/redo04.log',

'/ora_bak/oradata2/redolog/redo04.log') Size 16m Reuse;

SVRMGRL> ALTER DATABASE Add Logfile Group 5

('/opt/oradata/app/redo05.log',

'/ora_bak/oradata2/redolog/redo05.log') Size 16m Reuse;

SVRMGRL> ALTER DATABASE Add Logfile Group 6

('/opt/oradata/app/redo06.log',

'/ora_bak/oradata2/redolog/redo06.log') Size 16m Reuse;

Step 2: Do LOG SWITCH manually to make new Redo logfile work.

SVRMGRL> ALTER SYSTEM SWITCH LOGFILE;

This operation can perform one to several times, making the old redo logfile into the inactive state.

Step 3: Delete the old redo logfile.

SVRMGRL> ALTER DATABASE DROP LOGFILE GROUP 1;

SVRMGRL> ALTER DATABASE DROP LOGFILE GROUP 2;

SVRMGRL> ALTER DATABASE DROP LOGFILE GROUP 3;