Moving an Oracle Database to ASM

In this post I would like to describe the process for moving all of your Oracle database files into ASM. I will cover moving them all, control files, redo, temp, spfile, and of course data.

There are many advantages to moving files into ASM, but I think one of the coolest is that it is a cluster filesystem. So, with all your files loaded into ASM, it becomes very easy to start your database on a different host that has the same disk group mounted. Having a standby database in ASM opens up even more possibilities, but more on that in a future post.

Copy the datafiles

I have used this technique to move datafiles to a different SAN. It can be done while the database is up and running. You can allocate multiple channels to get a parallel effect.

backup as copy to destination '+DATA' database;

Move the controlfile into ASM

At this point, you need to start your outage.

Re-point to a controlfile in ASM

alter system set control_files = '+DATA' scope=spfile;

shutdown immediate;

startup nomount

--controlfile will be restored from its original location to +DATA. 
restore controlfile from '/home/oracle/app/oradata/ATW/control01.ctl';

Mount the database, rename the tempfile (it will be recreated when we open the database

alter database mount;

run {
set newname for tempfile 1 to '+DATA';

switch tempfile all;
}

Rename the datafiles to use the ASM copies, recover and open the database.

--This command renames the datafiles to the most recent image copies, which should be the ones we created with our backup command
switch database to copy;

recover database;

alter database open;

At this point all your temp files and data files should be in ASM

select name from v$tempfile;
select name from v$datafile;

Create redo logs in ASM

alter database add logfile '+DATA';
alter database add logfile '+DATA';
alter database add logfile '+DATA';

select member from v$logfile;

After you have created the necessary number of redo logs in ASM, switch logs and wait for the old logs to become inactive, then drop them.

select group#,status from v$log;

alter system switch logfile;

--as they become active, you can drop each group
alter database drop logfile group 1;
alter database drop logfile group 2;
alter database drop logfile group 3;