This article provides information on setting up the correct NIC teaming policies to allow iSCSI port binding.
Port binding is required for iSCSI vmkernels when they are in the same subnet. For example, you might assign an IP address of 10.16.156.66 to the VMkernel adapter you want to use for iSCSI. The routing table then contains an entry for the 10.16.156.x network for this adapter. If you then set up a second adapter for iSCSI and assign it an IP address of 10.16.156.25, the routing table contains a new entry for the 10.16.156.x network for the second adapter. However, when the TCP/IP stack reads the routing table, it never reaches the second entry, because the first entry satisfies all routes to both adapters. Therefore, no traffic ever goes out on the second iSCSI vmkernel adapter, and all IP storage traffic goes out on the first iSCSI vmkernel adapter.
Note: Since the ESXi host receives a routing table entry automatically for each vmkernel on the host, it is not recommended to override the default gateway on the vmkernel unless layer 3 connectivity is required.
Symptoms:
Multiple NICs within the same vSwitch disallow port binding due to the default NIC teaming policies.