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I am working to standardize the iSCSI networking for 2 hosts. I have attached a diagram showing how each of the hosts are currently setup. My question posed, which method is better, and why?

iSCSI_Setup.pdf (261 KB)

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With only two hosts, you don’t hook up a SAN at all. You use local storage. No value to a SAN, but loads of dangers and costs, with just two hosts.

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The full setup is 9 hosts and 2 SANS with a little over 40 TB of storage.

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That’s far better. How many switches, still two?

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You don’t need separate vSwitches, just make a single “iSCSI” vSwitch and then setup iSCSI port bindings for each physical NIC connection to the iSCSI Network.

Example:

vSwitch2

->vmk1->iSCSI1->X.X.X.81->MTU 9000->override failover order->move all but one physical nic to unused.

->vmk2->iSCSI2->X.X.X.82->MTU 9000->override failover order->move all but one physical nic to unused.

rince and repeat this process for each “NIC”

Now under “storage adapters” choose iSCSI->properties->Network. Add each of the NICs to enable iSCSI port binding.

Now add your LUNs/Volumes/datastores. Once added->properties->manage paths->round robin->change->OK

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So for this question… you are purely looking at the options of vSwitch fabric setup?

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Yes sir.

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If you’re going to stick with one of your two choices you have represented there, stick with the one on the right, the one with just 2 “iSCSI” vSwitches.

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I am being told by VMware that port binding will not work with multiple fault domains.

Port Binding Port binding is used in iSCSI when multiple VMkernel ports for iSCSI reside in the same broadcast domain and IP subnet to allow multiple paths to an iSCSI array that broadcasts a single IP address.

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Yes, this is why I said you only really only need a single “iSCSI” vSwitch, but if you already have two separate “iSCSI” networks/VLANs then you’re better off with your “right side” of your image setup.

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@purduepete007 , Thank you for your replies! Could you please help me understand why the right side is better than the left? I know that both will work but I am not sure of the pros/cons of either.

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Only because it’s less complicated. In my opinion those extra vSwitches are adding unnecessary complexity.

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I have 4 different brands of SANs in my environment and I run them all the same way. Single “vlan/subnet”, I think what you’re referring to as a “domain” with iSCSI port binding and my pathing seems to work just fine for each.

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Be aware certain arrays support multiple fault domains (others don’t).

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This. DHorsleyJr, You should definitely stick with the right-side option as the left one is nothing more than over-engineering. ISCSI-binding should be turned on if vmnic0 and vmnic1 are in the same subnet.

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