server 2012 R2 thinks there are new nics after modifying the nic speed in VC server profile

[jorgen_rosen]

Hi.

Last week i had an issue with our hyperv cluster in our c7000 enclosure environment.

our environment consists of 4 c7000 enclosures with flexfabric modules. 2 of the enclosures are running on vc 4.45 and 2 are on 4.31.

we have several of hyperv cluster consisting of bl460 Gen8 blades.

what i did was that i modified the maximum speed on the csv nic on all servers sofar so good. but later when i restarted one of the hosts all network configuration in the os was gone i also noticed in device manager that there where 6 nics greyed out and then there was 6 new unconfigured nics. i tried to reboot another server same thing again. It looks like all blades in the enclosures with vc 4.45 have this issue i havent seen this in the vc 4.31 enclosures. Anyone ever seen this behavoiur?

/regards Jorgen

[Mark Stratton]

In a Virtual Connect Firmware 4.4x environment, Whenever a Server Profile is applied on a Server Blade having SR-IOV disabled at System BIOS level, also known as RBSU (ROM-Based Setup Utility), Virtual Connect automatically enables SR-IOV in the System BIOS and it may result in network outage due to new Network Interface enumeration created by Operating System after the Server reboot. This becomes an issue for the Server environment where Server Administrator wants to disable SR-IOV at BIOS level for some reason and Virtual Connect enabling it automatically whenever the Server Profile is applied.

Applying Virtual Connect Server Profile enables SR-IOV at System BIOS level whenever VC detects SR-IOV capable CNA (Converged Network Adapter) installed in the Server Blade, irrespective of whether Virtual Functions have been configured or not in Virtual Connect Manager.

As aa workaround:

Whenever a Server Profile is applied and the server is rebooted, disable SR-IOV manually in the System BIOS as shown below and then bring up the Operating System:  Launch RBSU by pressing “F9” while booting => Select “Advanced Options” => Select “SR-IOV” => Select “Disabled” => Press “F10” to save and exit