Just been reviewing a customer's Vmware and 3PAR iSCSI setup. Whenever I have implemented iSCSI before, I have created 2 separate iSCSI network fabrics with different IP ranges and bound 2 separate vmkernel ports to load balance properly. This setup has a network stack, and all iSCSI interfaces on the array are in the same subnet, a single vmkernel portgroup has been configured with the 2 NICs in, so when using fixed mode with no manual load balancing all the IO goes through one NIC only.
This got me thinking, If i simply manuaklly balance the paths, or even better use ROund Robin, is this the optimum setup? I want to unstack the switches as if the master switch goes, both switches go, but can I simply use both switches in the same subnet and add the appropriate targets into the iSCSI discovery settings? Any downside to this setup?
