2012r2 Hyper-V

Hosts: HP G5

I have a lab with two hyperv servers and a cheap iscsi device. The Hyper-V servers have 4 physical network adapters. Two are pointing to the iSCSI and the last two are on two different physical user networks. I set up both vm host servers to point to the iscsi target and built a few VMs on hyperv host 1.

After a few weeks of playing around I went to adjust a VM to have a nic on both networks. Without realizing what the option was, I selected private for the network adapter type in the configuration of the VM host. Looks like it should have been external...

In a matter of seconds everything in the lab started to fail. The host lost connection to the user network as well as the iSCSI network.

After playing around a while I noticed that the physical network adapters were completely missing from the configuration which is why I couldn't even attach using the hyper-v admin tools. However, there were two new adapters installed called "Hyper-V Virtual Ethernet Adapter #2" and Adapter #3 but no physical nics (this is looking through the host console). I assume those adapters shouldn't be there because my second host (and working) does not have them listed; it just has the physical network adapters.

In the name of time and wanting to get this back online, I moved all the VMs to the second host and started them up (some I had to fight to get on the new server since the XML files went missing on the hard down).

Now I'm back to figuring out what was going on with this original host so I can work with the high availability features.

Any idea what could be going on and/or how to get the physical network adapters back? I could just reformat, but that's not the point with this exercise. I want to understand what happened and how to fix it (that's the point of this lab).

  • I don't quite understand. Only an External or an Internal vSwitch should create a vEthernet adapter. Can you show us screenshots of your vSwitches in Hyper-V and your Network Connections in Control Panel\Network and Internet\Network Connections? – joeqwerty Nov 22 '14 at 17:03
  • stupid; it won't let me add a screen shot because I need 10 rep. I can't connect the admin console to it so the only thing I could do anyway is a snapshot with my phone camera. When I go into network interfaces from the console all I see is: Index 19 Hyper-V Virtual Ethernet Adapter #2 Index 22 Hyper-V Virtual Ethernet Adapter #3 On the other server I see all of the intel nics. I did see the intel nics before I made the mistake above. But for some reason that server is no longer seeing the network interfaces; just the virtual interfaces. – DaBlue Nov 22 '14 at 17:56
  • All I can get to is the console; not the control panel, etc... – DaBlue Nov 22 '14 at 17:57
  • Found the resolution. I had to remove the virtual switch using remove-vmswitch per this article: altaro.com/hyper-v/… Once I removed the virtual switch, the nics came back! – DaBlue Nov 22 '14 at 18:55

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