SCVMM - Migrating to converged network config - VM network issues

Richard Goodman 1 Reputation point
2020-12-02T17:06:05.877+00:00

I have an existing 2012 R2 clustered Hyper-V environment with 4 hosts that are partially using the old 2008 network config style. I need to move the VLANS in the Non-Converged setup below to the Converged setup on the teamed 10 GB NICs.

The issue I'm having is when I create the new VLAN-based Logical Networks, it won't let me create new VM Networks, it states "There were no resources available to automatically create VM subnets for this VM network". I'm afraid if I remove these existing VM networks and/or Logical networks, it will also update my production hosts with the change causing the servers to lose network connectivity. Is there a way to do this without causing any down time? My SCVMM Version is 3.2.8453.0. Thanks in advance.

Using Converged - 2 Teamed 10GB NICs

  • VLAN 7 - 172.16.107.0/24 (Logical network VLAN based)
  • VLAN 65 - 192.168.65.0/24 (Logical network VLAN based)
  • VLAN 66 - 192.168.66.0/24 (Logical network VLAN based)

Using 2008 Non-Converged design - All use individual 1GB NICs

  • VLAN 4 - 172.16.104.0/24 (Logical network using "One connected network)
  • VLAN 5 - 172.16.105.0/24 and - VLAN 6 - 172.16.106.0/24 (Logical network using "One connected network)
System Center Virtual Machine Manager
0 comments

1 answer

Sort by: Most helpful
Most helpful Newest Oldest
  1. teiva Rodiere 0 Reputation points
    2023-06-12T00:10:37.1533333+00:00 
    	I realise this is a fairy older thread, but i spent time on this and found a possible resolution for why i had encounter this error message.

	This error occurs because on the logical switch you are trying to create the VM network on has no spare "Subnet" defined.

	There must be a spare VLAN/IP Subnet definition in the Network Site before you can create a VM Network (or an IP Pool).

	Solution: Add a new subnet under Network Sites.

	Steps: SCVMM -> Fabric -> Logical networks. Edit the properties of the logical network in question. Navigate to the Network Sites section and a new subnet under "Associated VLANs and IP Subnets" by clicking on the "Insert row" button. Once you have saved this, go back and create a new VM Network and/or IP Pool.

	Hope this can help somebody else down the track.
    0 comments