Configuring vSphere standby adapters

VMware vSphere allows a very flexible administration interface for networking. IT pro Rick Vanover shows how to configure the standby adapter option in the standard virtual switch.

Depending on a number of factors, virtualization administrators may want to designate network interfaces for certain roles. The most common use case is if a data center is limited in the higher performing network interface ports. This can include a limited number of 10 Gb/s Ethernet ports, with plenty of 1 Gb/s ports. This can also occur in situations where 1 Gb/s ports are limited, and there are plenty of 100 Mb/s ports.

VMware's vSphere offers two types of network switches for ESXi (and ESX) hosts: the standard virtual switch (vSwitch) and the new vNetwork Distributed Virtual Switch (vDS). The standard virtual switch has been around in a few manifestations since ESX 2, and the vDS was added with vSphere 4.

For the standard virtual switch, the underlying interfaces can be configured for an explicit failover order. For example, if each ESXi host only has one of the higher performing network interfaces for a standard virtual switch, an explicit failover can be configured to put the slower switch only as a failure node (Figure A). Figure A

Click the image to enlarge.

This configuration has the 10 Gb/s interface, vmnic0, as the active adapter for the vSwitch0 configuration. The slower interface, vmnic1, has a 1Gb/s connection and is listed as a standby adapter. If vmnic0 fails, vmnic1 will be able to take the load of the standard virtual switch.

Functionality may not be affected in this situation unless any configuration maximums are impacted. The most obvious example is simultaneous vMotion operations for 10 Gb/s connections compared to 1Gb/s connections.

If all vmnic interfaces are the same rate, the default configuration of having them both configured as an active adapter is preferred for even distribution of the nodes on the standard virtual switch through the originating virtual port ID load balance policy.

How do you configure the standard virtual switch with a particular failover order? Share your configuration strategies.