If you want to use ASM feature of Oracle 10g or later, then configure the Oracle ASM using the Database Configuration Assistant. You need to configure the ASM only once, from the node on which you installed Oracle first.
Review the procedure to configure ASM for Oracle database.
To configure ASM for the Oracle 10g or Oracle 11g database
Set the DISPLAY variable and start the Oracle Database Configuration Assistant as Oracle User.
# dbca
In the Operations dialog box, select the Configure Automatic Storage Management option and click Next.
In the Database Templates dialog box, select a template to create the database and click Next.
In the Database Identification dialog box, enter or select a unique name and SID for the global database and click Next.
In the Storage Options dialog box, select the Automatic Storage Option and click Next.
Review the warning message and click OK. Make sure that the Oracle clustering daemon is running.
In the Create ASM Instance dialog box, specify the ASM SYS user password and click Next.
In the ASM Disk Groups dialog box, choose to create a new disk group or add disks to an existing disk group.
In the Change Disk Discovery Path dialog box, enter the path name.
Depending on the disk device you want to use for ASM, enter the disk discovery path.
Follow the wizard instructions and complete configuring the Oracle ASM.