On each host that you want to add to a vSphere HA cluster, you must configure two different networking switches so that the host can also support vSphere Fault Tolerance.

To enable Fault Tolerance for a host, you must complete this procedure twice, once for each port group option to ensure that sufficient bandwidth is available for Fault Tolerance logging. Select one option, finish this procedure, and repeat the procedure a second time, selecting the other port group option.

Multiple gigabit Network Interface Cards (NICs) are required. For each host supporting Fault Tolerance, you need a minimum of two physical gigabit NICs. For example, you need one dedicated to Fault Tolerance logging and one dedicated to vMotion. Use three or more NICs to ensure availability.


The vMotion and FT logging NICs must be on different subnets. IPv6 is not supported on the FT logging NIC.


In the vSphere Web Client, browse to the host.


Click the Manage tab and click Networking.


Click Actions > All vCenter Actions > Add Networking.


Select VMkernel Network Adapter on the Select Connection Type page and click Next.


Select New Standard Switch and click Next.


Assign free physical network adapters to the switch and click Next.


Provide a Network label and enable the services you want and click Next.


Provide an IP address and subnet mask and click Finish after reviewing your settings.

After you create both a vMotion and Fault Tolerance logging virtual switch, you can create other virtual switches, as needed. Add the host to the cluster and complete any steps needed to turn on Fault Tolerance.


If you configure networking to support FT but subsequently disable the Fault Tolerance logging port, pairs of fault tolerant virtual machines that are powered on remain powered on. If a failover situation occurs, when the Primary VM is replaced by its Secondary VM a new Secondary VM is not started, causing the new Primary VM to run in a Not Protected state.