WAC Wizard 3 Node switchless

Hi @Daniel Fabian ,

For a 3-node, switchless HCI cluster, you would need two storage NICs per node (a single 2-port NIC like you have also works for this). The reason for this is because each node would need to connect to the other two nodes of the cluster directly. This is in addition to at least one other NIC that would be used for management and VM traffic (could be more). It is also HIGHLY recommended to put these two storage NICs onto separate subnets/VLANs due to the way SMB multichannel establishes connections over the storage networks. If you put both ports on the same subnet, SMB multichannel will assume each host should be able to connect to all storage NICs on both hosts and will attempt to do so. However, because it will only be able to connect to the directly-attached NIC, you will see some errors in the event logs as the cross-connection attempts would fail.

Also, we don't recommend using APIPA addresses for the storage adapters. As the traffic going across those storage adapters won't be routable, you could assign pretty much any address to those adapters just so long as they don't conflict with an actual address on your local network. Another reason APIPA is not recommended is because these address will change at reboot, so it may take a bit longer to rediscover the endpoint. Finally, an APIPA address is used by the cluster adapter once it comes online (by-design), so you want to avoid having any subnet overlap there as well.

That said, I tested this configuration and attempted to create a cluster via Windows Admin Center. I too received the same error that you noted above, and WAC would not allow me to proceed with testing. I did attempt to put all of the addresses on the same two subnets just to see what would happen. What I found was that WAC failed the connectivity tests (as expected). If I were to click on the 'Details' next to the failure, it showed me that the ping between the non-directly connected NICs was what failed. However, it did allow me at this point to continue with the cluster creation if I wanted.

Unfortunately, WAC doesn't cover every possible scenario for how clusters could be configured. For this scenario, it seems it would currently be better suited to build the cluster via PowerShell initially. This way, you can configure the optimized addressing scheme keeping each interconnect on its own subnet. Once the cluster is built, you could then manage the cluster via Windows Admin Center without issue.

Hope this helps!
Trent