Creating Online Redo Logs in an ASM Disk Group Location

Creation of redo logs on ASM disks is straight-forward. If the database was configured to use ASM from the beginning then the existing online redo logs will already be on ASM disk groups. Assuming that the parameters DB_ONLINE_CREATE_LOG_DEST_n or DB_CREATE_FILE_DEST are set, you can simply issue the alter database add logfile command and Oracle will add a new redo log group to your database for you as seen in this example:

Alter database add logfile size 100m;

You can also manually add a redo log file group to a disk group if you prefer using SQL such as the following which will create a new logfile group, and multiplex it, between two ASM disk groups:

Alter database add logfile
('+COOKED_DGROUP1','+COOKED_DGROUP2')
 size 100m;

Defining an ASM Disk Group Location as an Archived Redo Log Storage Area

Once you have created an ASM disk you may use it as the storage for archived redo logs. Set one of the LOG_ARCHIVE_DEST_N parameters to point to that ASM disk group as seen in this example:

Alter system
set log_archive_dest_1='location=+COOKED_DGROUP2';

You can check the ASM instance and see the new archived logs being created as seen in this example code:

SQL> select a.group_number, b.name, a.incarnation, a.file_number, a.type
  2  from v$ASM_DISKGROUPSb, v$asm_file a
  3  where a.group_number=b.group_number
  4  and a.type='ARCHIVELOG';

GROUP_NUMBER NAME                           INCARNATION FILE_NUMBER TYPE
------------ ------------------------------ ----------- ----------- -----------
           2 COOKED_DGROUP2                   613091705         258 ARCHIVELOG