Consider the following setup:
Windows 2008 R2, MPIO feature installed. Two iSCSI NICs (not bonded), 1Gb each.
Storage: Compellent, 2x 1Gb iSCSI ports, single controller.
In my tests I have confirmed that using Round Robin MPIO, both iSCSI NICs on the host are active during a single-worker IOMETER test. Both iSCSI NICs on the storage are also active during this test. I am seeing about 50% to 60% utilization on each host NIC, and I would expect more. I am using a crappy D-Link switch at the moment and this certainly is not helping, so I'm not super concerned about this yet.
My question is this: instead of "how can I make this particular setup perform", I would like to know, more generally, if round robin (active/active) MPIO allows me to get greater than 1Gb bandwidth from the host to the storage, using a single I/O stream (like copying a file, or running a single worker IOMETER test).
If yes, why? If no, why not?