Before you start configuring FT in your vSphere Infrastructure, you should have the prerequisites configured.

Infrastructure prerequisites:

• Your ESXi host should support vLockstep technology to support FT.
• All CPUs must be vMotion-compatible or the cluster must have EVC enabled.
• Intel CPUs must be Sandy Bridge or later. AMD CPUs must be Bulldozer or later.
• All your ESXi hosts should run on the same build and have a license to run FT VMs.
• Shared storage should be between the ESXi hosts.
• You should have an HA cluster enabled for FT to work
• You should have a dedicated NIC for the FT logging network and a separate vMotion network.
• Host certificate checking must be enabled in the vCenter Server.

VM prerequisites:

• VMs must be configured with four or fewer CPUs.
• The VM's disk must be 2 TB or smaller.
• There are no non-replayable devices on the VM.
• Snapshots must be removed before FT can be enabled on the VM.
• vMotion is supported on FT-enabled VMs, but you cannot vMotion both the primary and secondary VMs at the same time.
• Storage vMotion is not supported on FT-enabled VMs.

Once the requirements have been met, you can work on the actual FT configuration. First, we will configure a VMkernel port for FT logging:

1. Using vSphere Web Client, log in to the vCenter Server.
2. Select Hosts and Clusters on the Home Screen.
3. Select an ESXi host, then go to the Configure tab.
4. Click on VMkernel adapters under the Networking section.
5. Click on Add Host Networking to add a VMkernel port.
6. Select VMkernel Network adapter as the connection type. Click on Next.
7. Select an existing switch or create a new switch. Click on Next.
8. Give the VMkernel port a label and specify a VLAN number (optional).
9. Select the checkbox for Fault Tolerance logging and click on Next:

10. Specify DHCP or enter the IP address and Subnet Mask on the IP Settings page. A static IP is preferred over DHCP. Click on Next.
11. Review the configuration and click Finish.

Now as you have configured VMkernel for FT logging, you should be able to enable your VM for FT protection, as follows:

1. Choose the VM, right-click on it, and navigate to Fault Tolerance | Turn on Fault Tolerance.
2. Select the datastore for the secondary VM. Click on Next.
3. Select the host for the secondary VM. Click on Next.
4. Review the selections and click on Finish.
5. Once the setup is complete, you will be able to see the FT status, Secondary VM location, and Log Bandwidth information for the Fault Tolerance tile on the VM's summary tab:

6. To test the FT feature, right-click on the VM, select Fault Tolerance, and click on Test Failover.