---
title: "VMware Fault Tolerance"
description: "Find out how to assure continuous availability of your virtual machine by using Fault Tolerance"
url: https://docs.ovhcloud.com/en/guides/hosted-private-cloud/powered-by-vmware/fault-tolerance-continuity
lang: en
lastUpdated: 2020-07-07
---
# VMware Fault Tolerance

## Objective

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.


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

## Requirements

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

## Instructions

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

![Fault Tolerance](/images/hosted-private-cloud/powered-by-vmware/vmware-fault-tolerance/FT.png)
A configuration window will open, prompting you to make choices for the secondary VM.

- Datastores

![Fault Tolerance](/images/hosted-private-cloud/powered-by-vmware/vmware-fault-tolerance/FT1.png)
- The host

![Fault Tolerance](/images/hosted-private-cloud/powered-by-vmware/vmware-fault-tolerance/FT2.png)
Finally, a summary of your choices is displayed. Validate to enable FT on your virtual machine.

![Fault Tolerance](/images/hosted-private-cloud/powered-by-vmware/vmware-fault-tolerance/FT3.png)
Your virtual machine is now protected by **Fault Tolerance**, its icon is different and it will show as "primary".

![Fault Tolerance](/images/hosted-private-cloud/powered-by-vmware/vmware-fault-tolerance/FT4.png)
Several operations are now available according to your needs.

![Fault Tolerance](/images/hosted-private-cloud/powered-by-vmware/vmware-fault-tolerance/FT5.png)
## 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](https://docs.vmware.com/en/VMware-vSphere/6.7/com.vmware.vsphere.avail.doc/GUID-F5264795-11DA-4242-B774-8C3450997033.html) for more details on the topic. A list of incompatible features and devices is available on [this page](https://docs.vmware.com/en/VMware-vSphere/6.7/com.vmware.vsphere.avail.doc/GUID-C1749AD4-70E2-406C-864C-719F54BF1BC1.html).

## Go further

Join our community of users on [https://community.ovh.com/en/](https://community.ovh.com/en/).