Confused about separate vSwitch requirement on HW Dependent iSCSI HBAs

So I'm setting up a new ESXi 4.1 Update 1 system that involves two hosts, each with a Broadcom 5709 Hardware Dependant adapter containing two NICs, and a centralized iSCSI SAN. I've followed the "iSCSI SAN Configuration Guide ESXi 4.1" and configured each NIC on the broadcom card on it's own separate switch. From reading the guide, this is supposedly neccessary:

If your host has more than one physical NIC for iSCSI, for each physical NIC, create a separate iSCSI port using
1:1 mapping.
To achieve the 1:1 mapping, designate a separate vSwitch for each network adapter and iSCSI port pair. See
Figure 2-2.

If you look on page 38 at Figure 2-2, you'll see that each NIC is now configured to its own vSwitch.

While it seems a little over the top to have one switch per iSCSI adapter, I wouldn't care if I could figure out how to team/bond or achieve multipathing afterwards. I can't seem to get more than one connection per host to my SAN with this setup, so I'd like some guidance on that.

I'm eventually going to have a total of four 5709 NICs on each host, and I'd like to dedicate one for vMotion, one for HA, and the other two in a bonded/teamed configuration for my VM management traffic.

Can anyone provide some suggestions or steer me in the right direction?

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when you create the vswitch just chose multiple adapters or if you go to the vswitch properties -> network adapters you can add an additional nic to the setup
Justin CAWS Solutions ArchitectCommented:
You can accomplish the same thing by using a single vSwitch with multiple port groups, each with a vmknic, and assigning a different active adapter to each.  The goal is to have multiple vmknics with multiple IP addreses bound to different physical adapters.  Within ESX networking, an iSCSI IP connection is routed over one of the available uplinks based on your teaming policy.  If you have a single vmknic on the iSCSI vSwitch with two uplinks, only one will be used per iSCSI target connection. VMware's reasoning for this setup is that they want you to use the new multipathing features of vSphere.

Here is a great (and I mean great) explanation of iSCSI on VMware by Chad Sakic:
BigchinganAuthor Commented:
c0s, I know I can add additional NICs, but the setup guide says to add each dependent HW iSCSI adapter to it's own vSwitch to achieve a "1:1" mapping.


So can you tell me what advantage (if any) I'd achieve by having each iSCSI port bound to a different vmnic and vmhba on its own vSwitch? Why does the setup guide explain to do it that way rather than using a single vSwitch?
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do you have a link to the guide that you are following? i would like to take a look at it for clarification
Justin CAWS Solutions ArchitectCommented:
The doc is at:    Page 37

The advantage is that when you bind multiple physical adapters to your software iSCSI adapter it allows you to use multiple paths to your storage, as opposed to standard vSwitch networking in which only on path would be used.  Check out that link I posted earlier, it explains everything in way more detail than I can write out here.  

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BigchinganAuthor Commented:
BloodRed, I'm going ahead and combining them onto a single switch so I can achieve the round-robin style of teaming. I think the guide you posted above doesn't necessarily say NOT to do it, it's just not very clear. The way I was interpreting the guide the first time was counterintuitive to what I would expect was the ideal situation.

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