We actually are making a POC to migrate our infra to 10Gb/s. We use RHEL6.7 on HP DL360p servers. The 10Gb/s cards are Intel Corporation 82599ES 10-Gigabit SFI/SFP+.
The ixgbe drivers we use are 4.0.1-k
It seems that when we start an 10Gb/s interface (ifconfig ethX up) without SFP connected on it, the average load of the server increase ( about + 0.5) and we encounter many freeze while using SSH ==>
We notice Unix events/X process in uninteruptible state as follows :
for x in `seq 1 1 100`; do ps -eo state,pid,cmd | grep "^D"; echo "----"; sleep 0.1; doneD60 [events/9]
If we shut the interface (ifconfig ethX down), the problem disappears.
We did the same tests with 4.1.2 driver version and we don't have freezes anymore, but we still have process in uninteruptible state (but this time , it's ixgbe process):
for x in `seq 1 1 100`; do ps -eo state,pid,cmd | grep "^D"; echo "----"; sleep 0.1; done
D 61855 [ixgbe]
D 61855 [ixgbe]
When we start the interface with a SFP module connected on it (even without fiber), we don't see the problem (any driver version).
It looks like there is some kind of blocking behavior that occurs when we start an 10Gb/s interface without SFP connected on it (maybe some protocol advertisement, or something like that..).
Do you have some clue on this behavior ? I know there is no reason to start an interface without SFP connected, but still, maybe it could reveal some side effects ..
Good day. Further checking on this. I am sorry we do not know what caused the issue. This might be due to the reason of some incompability in the driver in the previous version. It is recommended to update to latest version.
Thanks for your answer.
Yeah we tried with newer drivers (not the last but the 4.1.2) and the SSH freezes disappeared. However when we did notice that this time, the ixgbe process was often in uninteruptible state (and no more Events).