Adding new NICs to SQL Server Cluster

Question

Hi, we have 2-node SQL Server 2019 cluster in production. Former colleague did not use dedicated NICs just for inter-node heartbeat communication potentially causing issues on daily basis. I would like to add NIC/per cluster node in separate VLAN that would be used just for inter-node heartbeat communication. Is that doable on live cluster?

Answer 1

That depends on the hardware support (hot-add NIC).

In any case, you might want to consider performing the change on the passive node first, failing over, and repeating the change on the other node (once it becomes passive)

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hth

Marcin

Answer 2

Hi Bojan,

Thanks for your post. To add the additional the NIC, it is highly recommended to take action in the maintenance window as we need to affinity between pNICs and vNICs brings in flexibility to route network traffic across teamed pNICs. With this feature, you can increase throughput by mapping RDMA capable physical adapter with RDMA settings enabled vNIC. Also, you can route specific type of traffic (for example, live migration) to a higher bandwidth physical adapter. In HCI deployment scenarios, by specifying affinity, you can use SMB multichannel to meet high throughput for SMB traffic.

Reference: Set up networking for Hyper-V hosts and clusters in the VMM fabric | Microsoft Learn

Best Regards,

Ian Xue

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