We purchased Dell R720 servers with Intel x520 PCI Dual Port cards. DELL 10Gb SFP+ modules (GBics) were supplied however they do not work with the Intel Cards. Only Intel SFP+ modules as per below link are supported. Once we got the Intel Gbics network connectivity was restored.
http://www.intel.com/support/network/adapter/pro100/sb/CS-030612.htm
On the DELL R720 physical hosts I downloaded the latest ixgbe driver 3.9.13.4 and below are the results on the host –
The 10Gb dual ports are vmnic8 and 9, it sees the card but cannot list the driver or firmware version and is not visible in vSphere network apapters but shows up in the hardware list as below
lspci | grep vmnic8
000:066:00.0 Network controller: Intel Corporation 82599EB 10-Gigabit SFP+ Network Connection [vmnic8]
ethtool -i vmnic8
Can not get control fd: No such file or directory
If you run this command on the host you will see the error if the module or Gbic is not supported
less /var/log/vmkernel.log | grep -i 'unsupported SFP'
2012-09-17T03:52:51.272Z cpu0:4739)<3>ixgbe 0000:42:00.0: failed to load because an unsupported SFP+ module type was detected.
2012-09-17T03:52:51.291Z cpu0:4739)<3>ixgbe 0000:42:00.1: failed to load because an unsupported SFP+ module type was detected.