Single Dell Equallogic PS5000E array, fw 7.0.5, dual controller, NIC0 and NIC1 on each controller are on the iSCSI VLAN, NIC2 on each controller is on the management VLAN.
VMware vSphere 5.5, software iSCSI, each host has two physical NICs connected to the iSCSI VLAN. iSCSI traffic runs through a standard vSwitch which has two vmkernel ports, each vmkernel port has one physical NIC assigned as active and the respective other set to unused. Port bindings are set up correctly in the network configuration tab of the software iSCSI adapter.
The PS5000E will not be presented to the ESXi hosts and will not be used as VMDK datastore. The PS5000E will be presented as an iSCSI device to a VM than runs Windows Server 2012 R2, formatted with NTFS and used by that VM exclusively. The VM will have two virtual NICs on the iSCSI VLAN. VM will have Dell EqualLogic Host Integration Tools for Microsoft installed which should take care of the OS side of MPIO to the PS5000E.
The question is whether the ESXi hosts need the Dell EqualLogic Multipathing Extension Module for VMware vSphere to take full advantage of MPIO between a VM on those hosts and the PS5000E without that the storage is presented to ESXi?
It seems to me that the module is not required because the PS5000E is not presented to ESXi and any iSCSI traffic is pass-through, but I can't find an actual reference to back this up.
Sidebar discussion: The only reason to give the VM two virtual NICs in the iSCSI VLAN is to aggregate storage bandwidth in and out of the VM to the PS5000E.