This question is a follow-on from Dedicated NIC or dedicated port for iSCSI?

Excluding the hardware iSCSI initiator point that was made in the accepted answer to the above question, it seems that using separate port(s) on a multi-port NIC for iSCSI is pretty much going to meet the recommendation of using "seperate NICs" for iSCSI traffic.

I'm in the process of planning a small iSCSI installation that connects two cluster nodes to a storage array using redundant paths/switches via MPIO. As a result, each node has four physical network connections to the iSCSI switches.

Each machine has two quad-port NICs. Four ports are required for non-iSCSI traffic, and four for the aforementioned iSCSI traffic, meaning all eight ports will be in-use.

My question is this - If you have the luxury of multiple physical NICs in the box, should you split your iSCSI connections across the two NICs to cope with a NIC failure (in my case 2 ports each), or should you stick to keeping all iSCSI traffic on the single NIC? My hunch would be to separate the traffic, but I'd like to get the thoughts of those with more real-world experience of iSCSI than I. Am I going to hit some sort of unexpected complication doing it this way?

Although I've asked the question in the context of my particular example, I've tried to ask a general question that will hopefully be applicable to other similar configurations.

Any help greatly appreciated.


I'd split across physical NIC adapters, assuming similar functionality. Many high-end servers now have a number (4+) of onboard ports, so i I had an add-in card of a similar specification, I'd MPIO across the onboard and the add-in. If not, multiple add-in cards work well, too.

  • Thanks for the info. They're Dell PowerEdge with onboard Intel and a Dell Intel daughter board, so I'd imagine the hardware spec is very similar. – dbr Aug 13 '12 at 11:59
  • Same here, I spread iSCSI across different NIC's (one onboard NIC and one add-in to make sure a dead NIC doesn't kill all storage traffic). – pauska Aug 13 '12 at 12:10

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