> # Assigning LUNs to Storage Subsystems

> LUN masking and mapping restricts server access to specific LUNs. If LUN masking is enabled on a storage subsystem and if you want to perform additional LUN zoning in a Cisco MDS 9000 Family switch, obtain the LUN number for each host bus adapter (HBA) from the storage subsystem and then configure the LUN-based zone procedure provided in the "Configuring a LUN-Based Zone" topic.

> Note Refer to the relevant user manuals to obtain the LUN number for each HBA.

> Caution | If you make any errors when assigning LUNs, you might lose data.

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