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Example of a configuration with multiple LUN groups

Using multiple LUN groups enables you to partition the load over connections. This configuration is supported for most storage arrays. See the Interoperability Matrix to confirm that this configuration is supported with your storage array.

The following illustration shows how one FC initiator port pair (0c and 0f) on the Data ONTAP system accesses one LUN group over one storage array port pair, and a second FC initiator port pair (0a and 0h) accesses a second LUN group on the same storage array over a different storage array port pair.

Note: This configuration is referred to as stand-alone with two 2-port array LUN groups. A multiple LUN group configuration could have an HA pair instead of a stand-alone system.
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This multiple LUN group configuration enables you to spread the I/O across the RAID groups (parity groups) on the storage array. You set up your configuration so that different FC initiator port pairs access different groups of LUNs on the storage array. The Data ONTAP system sees any given array LUN over only two paths because a given LDEV (logical device) is mapped to only two redundant ports on the storage array. Each LUN group is accessed through a different target port pair.

Each LDEV is identified externally by a LUN ID. The LDEV must be mapped to the same LUN ID on all storage array ports over which it will be visible to Data ONTAP systems.

Note: The same LUN ID cannot refer to two different LDEVs, even if the LUNs using the same ID are in different host groups on a target port. Although LUN ID reuse is not supported on the same target port, LUN ID reuse is supported on a storage array if the LUNs are mapped to different storage array ports.

The following table summarizes the zoning for this example. Single-initiator zoning is the recommended zoning strategy.

Zone FC initiator port on the Data ONTAP system Storage array
Switch 1
z1 Port 0a Controller 1 Port B
z2 Port 0c Controller 1 Port A
Switch 2
z3 Port 0f Controller 2 Port A
z4 Port 0h Controller 2 Port B

See the Interoperability Matrix to determine whether multiple array LUN groups are supported for your storage array.