I've got four identical blade servers.
I've got Windows Server 2012 R2 on one blade and Xen on all the others.
On the Windows-hosted server (only) the 10GbE NICs cannot negotiate 10Gbit. They settle at 1Gbit only.
10GbE on Xen hosts works properly.
I've got DELL PowerEdge M1000e chassis with:
- 2x M8024-k 10GbE switch (A1, A2)
- 4x M620 identical blades with following NIC:
- slot A: Broadcom NetXtreme 10GbE 2P 57810s (the 10GbE card this issue is about)
- slot B: Broadcom NetXtreme GbE 4P 5719S (not related to issue, I hope)
All the available firmwares are identical and up-to-date.
Additional info & diagnostic
- The machine has previously been used under some *nix system (probably also Xen) and previous sysadmin had left no notice of any such problems (which would otherwise be expected). I therefore assume it was working properly.
- This happens on both ports. Both ports are on single card though.
- When I try to set speed manually at 10Gbit, I get Windowsy "network cable not attached" status.
- Windows has all the latest drivers.
- As stated above, the problem does not appear on Xen-hosted servers. It's Windows only.
- The configuration on both switches (A1 and A2) has been reviewed, ports are set to auto-negotiation and I found no other differences in the port configurations between Windows and Xen-assigned ports.
- This was the only machine with NIC partitioning enabled (NPAR+SR-IOV), but I have disabled it and it made no change.
Since I still believe it might be some weird Windows issue, I have posted this question to exclude any possible software sources of the problem, especially those which might be Windows-specific.
Do you have any hints where to look and what may be wrong?