Before we are able to test FT, we need an FT enabled virtual machine. After confirming that all the pre-requisites for FT are in place, you can then protect a virtual machine with FT. To do so, right click on the virtual machine and select ‘Fault Tolerance | Turn On Fault Tolerance’:
You will immediately receive a warning about the changes that will take place when FT is enabled for the virtual machine. These include converting the disks to think, disabling DRS for the virtual machine, and setting a reservation equal to the allocated memory:
Once you click ‘Yes’, a task will run to configure FT for the virtual machine:
The task will take a little while to run. Once it’s complete you can power on the VM. There will be an area on the VM’s summary tab showing that it is protected by FT:
Looking at the cluster’s list of virtual machines, we now see a secondary VM for the virtual machine protected with FT (note that there are on different hosts):
Another thing worth checking at this point is the host’s summary tabs, which will show how many primary and secondary powered on VMs there are on a given host:
Testing FT Failover
You can easily test FT failover by right clicking the FT protected virtual machine and selecting ‘Fault Tolerance | Test Failover’:
When you test failover, the VM will briefly become unprotected as it switches the secondary VM to primary, then sets up a new secondary VM.
Eventually, the status will switch back to protected.
FT Secondary Restart
You can restart the secondary virtual machine by right clicking on the FT VM, then from the Fault Tolerance menu, click ‘Test Secondary Restart’. When you do this, the VM temporarily becomes unprotected whilst it’s new secondary VM is started up.