Dell Unity: What is LUNz and how to correct (User Correctable)

LUN Z (or LUNz) on Dell Unity systems is a placeholder LUN that appears when no actual LUNs are assigned to a host. It represents the initiators of the Unity array and is non-usable, meaning it does not store data or serve any functional purpose. However, it can sometimes cause confusion in storage environments.

LUNz / LUN_Z showing on a host connected to a Unity array.

During creation, there is no Host LUN ID (HLU) 0 given to any of the LUNs presented to the host.

All Hosts should have an HLU 0 configured to it. 

How to Remove LUN Z:

1. Create a LUN 0: If you configure a LUN 0 for the host, LUN Z disappears automatically.
2. Unzone the Unity Array Initiators: If the Unity array is not in use with a specific host, you can remove zoning between the Unity array initiators and the host initiators at the fabric switch level.
3. Disable LUN Z in Unisphere:

• Log in to Unisphere.
• Select the host where LUN Z appears.
• Go to the Initiators tab.
• Double-click the initiator.
• Scroll to the Advanced section and clear the "LUN Z enabled" box.
• Click OK to save changes.

• KB Article 330420: What is LUN_Z or LUNz
• KB Article 490149: Dell EMC Unity: How to view and change LUN ID (HLU)
• The first LUN accessed by a Host is automatically assigned LUN ID (HLU) of 0.
• Changing the Host LUN ID value should be done in a maintenance window.