Refer to the exhibit.

ESXi multipathing is the correct control point because the design already exposes distinct iSCSI-A and iSCSI-B VMkernel paths. Multipath I/O maintains more than one end-to-end path between an ESXi initiator and the storage target, allowing the host’s path-selection policy to use available paths and to fail over when a NIC, fabric, switch link, or target path becomes unavailable. This improves scalability by distributing I/O across independent paths rather than making one logical Ethernet bundle the sole transport dependency. Cisco’s UCS iSCSI SAN-boot guidance explicitly covers ESXi operation with Multipath I/O, and Cisco validated designs commonly preserve physically and logically separate iSCSI fabrics. LACP is not the appropriate substitute for storage multipathing: it aggregates Ethernet links but normally hashes each flow to a member and does not provide the storage-aware path selection that ESXi and the iSCSI stack require. Generic vNIC teaming likewise provides link redundancy without creating independently managed iSCSI sessions to the target. Putting every initiator and target into one unsegmented subnet reduces fault isolation and does nothing to improve path selection or storage scalability. The correct design binds the iSCSI VMkernel interfaces to separate uplinks and uses ESXi multipathing so both storage paths are visible, monitored, and recoverable. This preserves redundancy and allows the storage stack—not merely the Ethernet layer—to make path decisions. Cisco UCS iSCSI SAN boot with ESXi MPIO

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