You can establish fault tolerance for virtual machines hosted by ESX servers that are part of a VMware HA cluster. When you enable VMware FT for a virtual machine, an identical copy of the virtual machine, called a secondary, is established on another host in the cluster. If the first virtual machine fails, the secondary virtual machine takes the original one's place, and a new secondary is created. This process helps provide uninterrupted virtual machine functionality, even in the event of failures. Before you can enable VMware FT, you must have VMware HA enabled and the CPUs of the servers hosting the virtual machines must support VMware FT.
After publishing an article about the CPU compatibility with VMware Fault Tolerance, my search for a white CPU began. The vLockstep technology used by FT requires the physical processor extensions added to the latest processors from Intel and AMD. In order to run FT, a host must have an FT-capable processor, and both hosts running an FT VM pair must be in the same processor family.
Richard Garsthagen’s “CPU-Host-Info” shows all the available options on both the Intel Q9400 and Q9550 marked true. I’ve used the Intel Q8200 in another white box and it didn’t work, so in order to use FT, you need FT and both the VT options. The next step is run through the Fault Tolerance Checklist.
You can enable VMware Fault Tolerance through the vSphere Client.
Connect vSphere Client to vCenter Server.
Prerequisites
The option to turn on Fault Tolerance is unavailable (grayed out) for a virtual machine to which any of the following conditions apply:
■ is not in an HA-enabled cluster
■ has one or more snapshots
■ is a template
■ is disconnected
■ resides on a host which is in maintenance or standby mode
■ is performing a record/replay operation
Procedure
1. Select the Hosts & Clusters view.
2. Right-click a virtual machine and select Turn Fault Tolerance On.
VMware Fault Tolerance requires eager zeroed thick disks. Virtual machines with thin provisioned or lazy zeroed disks must be powered off while enabling VMware Fault Tolerance in order for vCenter to complete this conversion.
The specified virtual machine is marked as a primary and a secondary is established on another host. Fault Tolerance is now enabled on 4 virtual machines :-)
