If you specify the LUN ID, System Manager checks the validity of the LUN ID before adding it. If you do not specify a LUN ID, Data ONTAP automatically assigns one.
Steps
1.
From the Home tab, double-click the appropriate storage system.
2.
In the navigation pane, click Storage > LUNs.
3.
In the LUN Management tab, click Create.
4.
Type or select information as prompted by the wizard.
5.
Confirm the details and click Finish to complete the wizard.