Deploy SMB Direct with InfiniBand Network Adapters


Applies To: Windows Server 2012 R2, Windows Server 2012

This topic explains how to deploy SMB Direct with InfiniBand network adapters.


When you deploy SMB Direct with an RDMA-capable network adapter, the network adapter functions at full speed with very low latency, while using very little CPU. You can use the InfiniBand series of networks adapters to take full advantage of the capabilities of SMB Direct.

Hardware and software requirements

Use the following requirements to implement and test this deployment:

  • Two or more computers running Windows Server 2012 R2 or Windows Server 2012

  • One or more InfiniBand network adapters for each server

  • One or more InfiniBand switches

  • Two or more network cables as required for the InfiniBand network adapters that you select. These are typically enhanced small form-factor pluggable (SFP+), QSFP, or QSFP+ connectors.

Example InfiniBand configurations

There are many options available for InfiniBand network adapters, cables, and switches. The following are some examples of configurations that you can use with Windows Server 2012 R2 or Windows Server 2012:

  1. Two computers using FDR (Fourteen Data Rate) InfiniBand network adapters. FDR InfiniBand has a 54 Gbps data rate. In this deployment, the minimum configuration is two network adapters and a network cable. You will need a system with PCIe Gen3 slots to achieve the 54 Gbps data rate. PCIe Gen3 slots are available on newer computer systems. If you use an older system, the network adapter will be limited by the speed of the older PCIe Gen2 host bus adapter.

  2. Ten computers using dual FDR InfiniBand network adapters. To increase throughput in a private cloud deployment, you can configure a two-node file server cluster, in addition to an eight-node Hyper-V cluster. For added performance and fault tolerance, use two InfiniBand network adapters for each system. In this configuration, you need 20 FDR InfiniBand network adapters and a 20-port FDR switch.

For additional information about the InfiniBand network adapters (and part numbers) that support SMB Direct, see the following blog post: Deploying Windows Server 2012 with SMB Direct (SMB over RDMA) and the Mellanox ConnectX-2/ConnectX-3 using InfiniBand – Step by Step.

Download and update the latest drivers

Although Windows Server 2012 R2 and Windows Server 2012 might include drivers for the network adapter, you should always verify that you have the latest version of the driver from the manufacturer of the network adapter. Follow the manufacturer's installation instructions to install the driver.

Configure a subnet manager

When you use an InfiniBand switch, you are required to have a subnet manager running. The best option is to use a managed InfiniBand switch (which runs a subnet manager), but you can also install a subnet manager on a computer that is connected to an unmanaged switch. This section discusses the options that are available for configuring a subnet manager.

Use a managed switch with a built-in subnet manager.

Many InfiniBand switches have an internal subnet manager that runs by default when the switch is powered on or runs when it is enabled by using the switch’s web interface.

If a managed switch is not available, you can use one of the computers running Windows Server 2012 R2 or Windows Server 2012 to run your subnet manager. You can use the OpenSM application that is provided by the OpenFabrics Alliance, which is available with some InfiniBand device driver distributions. The executable file for the OpenSM application is opensm.exe. Make sure that you install the tool as a service that starts automatically.


We recommend that you do not use OpenSM with an unmanaged switch in production environments.

For additional fault tolerance, make sure that you have two computers on your network configured to run OpenSM. Do not run OpenSM on more than two computers that are connected to an InfiniBand switch.

Configure the IP address

After you have installed the latest version of the drivers, you should configure the IP address for the network adapters. If you are using a DHCP server, the network adapters are automatically configured, and you can move ahead to the following section.

To assign an IP address to your network adapter, you can use IP Address Management or the Net TCP/IP cmdlets in Windows PowerShell. For more information, see Net TCP/IP Cmdlets in Windows PowerShell.

The following Windows PowerShell example shows how to assign an IP address to a network adapter called RDMA1, with an IP address of, and a DNS server at

Set-NetIPInterface -InterfaceAlias RDMA1 -DHCP Disabled
Remove-NetIPAddress -InterfaceAlias RDMA1 -AddressFamily IPv4 -Confirm:$false
New-NetIPAddress -InterfaceAlias RDMA1 -IPAddress -PrefixLength 24 -Type Unicast
Set-DnsClientServerAddress -InterfaceAlias RDMA1 -ServerAddresses

Verify the configuration

To verify that the configuration is working correctly, you can review configuration information about the network adapter and the SMB connection. For more information, see the Verify the configuration section.

Review the performance counters

There are several performance counters that you can use to verify that the RDMA-capable network adapters are being used and that the SMB Direct connections are established. For more information, see the Review the performance counters section.

Review the event logs for RDMA network adapters

You can use several events in the Windows event log to verify that the RDMA-capable network adapters are operational, and the SMB Direct connections are accessible. For more information, see the Review the event logs for RDMA network adapters section.

See also