What’s new in failover clustering: #07 SMB Multichannel & Multi-NIC cluster networks

This post was authored by Rob Hindman, Senior Program Manager, Windows Server

Getting the best performance

Building enterprise-grade solutions with Windows Server 2016 is now easier with the new Simplified SMB Multichannel feature in Failover Clustering. A Windows Server 2016 failover cluster will now automatically recognize and configure multiple NICs on the same subnet, greatly simplifying network design and implementation. SMB Multichannel helps customers to leverage high-bandwidth 10GiB, 40GiB, and higher networks. Since both RSS-capable and RDMA-capable NICs can be used, throughput for SMB traffic is greatly improved. The net result is faster solutions that take advantage of modern hardware and are easier to configure.

Both Hyper-converged and Converged cluster configurations are supported. In the Hyper-converged diagram below, there are two physical networks (subnets); the network with multiple NICs in each cluster node can be used for high bandwidth traffic, such as Virtual Machine Live Migration.

In the Converged network diagram below, multiple NICs are used in the network that spans the two clusters (the North-South network) to achieve high performance.

Note that multiple physical networks (subnets) are required to ensure that the failover cluster can continue to function in the event of a switch failure.

Automatic and on by default

No configuration is necessary to use this feature – the cluster will automatically detect and use all the NICs that are present. All of the NICs will be used for cluster heart beating, CSV, and cluster traffic. The cluster will also automatically use the IPv6 Link Local (fe80) IP Address resources on private cluster-only networks. Cluster validation has also been updated to check for multiple NICs on the same subnet.

Further details on the Simplified SMB Multichannel feature in Windows Server 2016 can be found here. A great article about SMB Multichannel can also be found here.


In summary, the new Simplified SMB Multichannel feature means that Windows Server 2016 failover clusters can automatically take maximum advantage of modern network switches and NICs. Great network throughput and security can be realized with SMB 3.1.1 – your users will love it!

To try this new feature in Windows Server 2016, download the Technical Preview.

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