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VMware Fault Tolerance

Find out how to assure continuous availability of your virtual machine by using Fault Tolerance

Last updated 7th July 2020


The Fault Tolerance (FT) functionality of VMware's vSphere allows to protect a virtual machine from hardware failures by cloning the VM on two separate hosts.

Fault Tolerance

This guide explains the usage of Fault Tolerance on your VMs.


  • vSphere HA activated
  • Resource reservation equal to 100% of memory
  • VMware Tools installed
  • Same generation processors
  • 4 vCPUs maximum


To activate Fault Tolerance, right-click on a VM, then click Fault Tolerance and Turn On Fault Tolerance.

Fault Tolerance

A configuration window will open, prompting you to make choices for the secondary VM.

  • Datastores

Fault Tolerance

  • The host

Fault Tolerance

Finally, a summary of your choices is displayed. Validate to enable FT on your virtual machine.

Fault Tolerance

Your virtual machine is now protected by Fault Tolerance, its icon is different and it will show as "primary".

Fault Tolerance

Several operations are now available according to your needs.

Fault Tolerance

The OVHcloud Resilience mode is a good way to test your FT-activated virtual machine for high availability.

Impossible and incompatible actions

On a virtual machine with Fault Tolerance enabled, it is no longer possible to perform certain actions or to use certain devices.

Please refer to this documentation for more details on the topic. A list of incompatible features and devices is available on this page.

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