Another new feature of VMware vSphere April is the power to use Fault Tolerance or FT. It is the power to have real high availability, ie, with earlier versions of VMware, provided by DRS, that if he fell a physical host, virtual machines running on it, go to run to another host, after a restart virtual machines. VMware FT is what gives us the possibility that virtual machines will not have to restart, and in case of fall of the ESX host with virtual machines, which are protected by FT will executed on another host without loss of service.

What is this? Enabling FT on a virtual machine in the background is enabled the execution of a second virtual machine copy of the first in another host, leaving the machine how to 'read', and only change its state if the primary virtual machine falls, based on vLockstep technology. That's the good, the bad, the conditions which have FT as of today, it is assumed that those conditions will disappear following versions. Requirements:

- ESX Host must be version 4 or higher.
- There should be an HA cluster.
- Processor / CPU ESX host these must be of the same family.
- Hyperthreading disabled.
- Logically, the MV may have no physical device connected to the host (CD, PCI adapter, floppy ...)
- The virtual machine must be on shared storage.
- Only one vCPU in the virtual machine.
- Setting up a network for VMotion with two NIC per host.
- Configure a network to Faul Tolerance Logging with 2 NIC per host.
- The secondary VM is running, waiting for the primary fails. Therefore consume resources, but not as the primary draw.
- If we DRS, protected virtual machines are not moved automatically between hosts.
- No snapshot can be made in these MV, nor, therefore, based backups using snapshots (or DataRecovery how VCB).
- MV They may not have USB adapters or sound devices.
- Not supported using MSCS (Microsoft Cluster Services) within the virtual machine.
- We can not use RAW or RDM, ie one LUN mapped directly against these virtual machines.
- On the use of virtual hard disks, no hot can be moved using Storage VMotion. Thin disks or may be, if not, to be Thick.

Once we meet the requirements, most of them logical, some how 1vCPU waiting for ... we continue to disappear.

First of all, when you create the virtual machine is to take the hard drive is configured for use with Fault Tolerance, marking "Such features as clustering Support Fault Tolerance."

We have two adapters to a network Giga for the log's of FT between all ESX host, as well as one for VMotion.

Once fulfilled all the requirements, enable FT is easy on the virtual machine we safeguard, with right-click "Fault Tolerance"> "Turn On Fault Tolerance"

We confirm that enable your FT, "Yes"

... Wait a few seconds while empowering ...

And we will see the different virtual machine, and click on it and go to the tab "Sumary" see that Fault Tolerance is enabled, as it indicates that the MV is protected.

If we go to the host that indicates how "Secondary Location", we will find out the virtual machine in Virtual Machines "how high, and if your console will be opened as read only.

By the way, if we try to enable FT in an environment where virtual servers are ESX, we must modify the file. Vmx virtual machine to protect by adding this in your configuration:

replay.allowBTOnly = TRUE