Lars Hecking writes:
There are more than one NIC-model with 82599EB and evidently not all work with the CentOS driver. What we're using successfully is X520-DA2:
Intel Corporation 82599EB 10-Gigabit Network Connection (rev 01)
What do you have?
http://www.intel.com/support/network/sb/cs-012904.htm
PCI id 151c = X520-T2.
Just to close this old thread: in a few months of operation, we have repeatedly run into problems where the servers just dropped off the network with pretty much nothing logged on the server or the switch side. The symptoms are strikingly similar to the problem described here (Peter K, you should have remembered :)
http://lists.us.dell.com/pipermail/linux-poweredge/2011-March/044417.html
and the same solution works for us - replacing the standard CentOS ixgbe driver with the latest from Intel.