I had been hacking around on a vsphere 5.5 host connected to an ESOS (storage distro running off usb flash drive). Did lots of fiddling around with SRP, trying to figure out how to get iSER working (no joy at this point). The storage server (supermicro x9scl-f) didn't seem to like the used connnectx-2 card I got on ebay (I would reboot, and the IB stuff would have just disappeared, despite the card being visible via lspci.) So I shelled out a little extra for a new connectx-3 card for the storage server. I discovered that if I reverted to the 1.9 (ethernet only) vsphere IB driver, the connectx-3 would connect to the connectx-2 as a 10gbe enet link (direct connect with QSFP+/QSFP+ cable.) I decided to replace the single port connectx-2 in the vsphere host with a dual-port card - since the same guy I got the other connectx-3 card from had more in stock, I bought another and swapped it in. To my surprise, vsphere and linux now report a 40gbe ethernet link! Good times I'd like to get iSER working to reduce CPU load on both sides, but SCST doesn't support that yet (that is the iSCSI target SW ESOS uses.) They do have an SCST branch in development supporting iSER, so I think I'll just wait it out until then. The other vsphere host only has 1gbe to the storage server, but it's a backup box anyway. I did throw the replaced connectx-2 card in that box, so I can at least do vmotion at 10gbe