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# ls -l /dev/raw/raw[1234]
crw-rw---- 1 oracle dba 162, 1 Jun 2 22:04 /dev/raw/raw1
crw-rw---- 1 oracle dba 162, 2 Jun 2 22:04 /dev/raw/raw2
crw-rw---- 1 oracle dba 162, 3 Jun 2 22:04 /dev/raw/raw3
crw-rw---- 1 oracle dba 162, 4 Jun 2 22:04 /dev/raw/raw4

Attention Linux Users! This article does not use Oracle's ASMLib I/O libraries. If you plan on using Oracle's ASMLib, you will need to install and configure ASMLib, as well as mark all disks using: /etc/init.d/oracleasm createdisk <ASM_VOLUME_NAME> <LINUX_DEV_DEVICE> . For more information on using Oracle ASMLib, see "Installing Oracle10g Release 1 (10.1.0) on Linux - (RHEL 4)".

Attention Windows Users! A task that must to be performed for Microsoft Windows users is to tag the logical drives that you will want to use for ASM storage. This is done using a new utility that is included with Oracle Database 10g called asmtool. This tool can be run either before or after creating the ASM instance. asmtool is responsible for initializing the drive headers and marks drives for use by ASM. This really assists in reducing the risk of overwriting a usable drive that is being used for normal operating system files.

Attention Windows Users! If you are running in Microsoft Windows, you will need to manually create a new Windows service to run the new instance. This is done using the ORADIM utility which allows you to create both the instance and the service in one command.

UNIX

# su - oracle
$ ORACLE_SID=+ASM; export ORACLE_SID
$ sqlplus " as sysdba"

SQL> startup
ASM instance started

Total System Global Area  75497472 bytes
Fixed Size 777852 bytes
Variable Size  74719620 bytes
Database Buffers  0 bytes
Redo Buffers  0 bytes
ORA-15110: no diskgroups mounted

SQL> create spfile from pfile='/u01/app/oracle/admin/+ASM/pfile/init.ora';

SQL> shutdown
ASM instance shutdown

SQL> startup
ASM instance started

Microsoft Windows

C:\> oradim -new -asmsid +ASM -syspwd change_on_install 
 -pfile C:\oracle\product\10.1.0\admin\+ASM\pfile\init.ora -spfile 
 -startmode manual -shutmode immediate

Instance created.

C:\> oradim -edit -asmsid +ASM -startmode a

C:\> set oracle_sid=+ASM
C:\> sqlplus " as sysdba"

SQL> startup pfile='C:\oracle\product\10.1.0\admin\+ASM\pfile\init.ora';
ASM instance started

Total System Global Area 125829120 bytes
Fixed Size 769268 bytes
Variable Size 125059852 bytes
Database Buffers 0 bytes
Redo Buffers 0 bytes
ORA-15110: no diskgroups mounted 

SQL> create spfile from pfile='C:\oracle\product\10.1.0\admin\+ASM\pfile\init.ora';
File created.

SQL> shutdown
ASM instance shutdown

SQL> startup
ASM instance started

ORA-15110: no diskgroups mounted

Notice also that we created a server parameter file (SPFILE) for the ASM instance. This allows Oracle to automatically record new disk group names in the asm_diskgroups instance parameter, so that those disk groups can be automatically mounted whenever the ASM instance is started.

Now that the ASM instance is started, all other Oracle database instances running on the same node will be able to find it.

Available (candidate) disks for ASM are discovered by use of the asm_diskstring instance parameter. This parameter contains the path(s) that Oracle will use to discover (or see) these candidate disks. In most cases, you shouldn't have to set this value as the default value is set for the supported platform. The following table is a list of default values for asm_diskstring on supported platforms when the value of the instance parameter is set to NULL (the value is not set):