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Turn on Fault Tolerance option is disabled (1010631)

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  • A virtual machine's Turn on Fault Tolerance option is greyed out
  • A virtual machine's Turn on Fault Tolerance option is disabled
  • You cannot turn on Fault Tolerance


For the Turn on Fault Tolerance option to be visible, these requirements must be met. If any of the following is not configured correctly, the option is not displayed. Ensure each of the following are properly configured:
  1. Ensure VMware software compatibility. All versions of the VMware software used in a Fault Tolerance environment must be compatible. Ensure that the versions installed at your site are listed as compatible in the vSphere Compatibility Matrix.

  2. On a hardware and guest operating system level, only certain processors and operating systems are supported. For more information on this support, see Processors and Guest Operating Systems that support VMware Fault Tolerance (1008027).

    Note: SMP (Multiprocessor) virtual machines are not supported with VMware Fault Tolerance at this time.

  3. Hardware Virtualization (HV) must be enabled in the BIOS for each host in the cluster. The process for enabling HV differs in each BIOS. For this reason, contact your hardware vendor for instructions on enabling HV.

  4. All ESX hosts used by VMware Fault Tolerance must be members of a VMware High Availability (HA) cluster. VMware HA must be enabled for VMware Fault Tolerance to function. Instructions for enabling VMware HA can be found in the vSphere Availability Guide.

  5. The ESX hosts that run the primary and secondary Fault Tolerance nodes must be running the same build of ESX. Additionally, patches have been released that contain improvements to the VMware Fault Tolerance features. For this reason, VMware strongly suggests updating to the most current version available. Instructions for updating hosts can be found in the VMware vCenter Update Manager Administration Guide or the ESX 4 Patch Management Guide.

  6. There are several important considerations relative to storage for VMware Fault Tolerance. Ensure each of the following are configured for your environment to enable VMware Fault Tolerance:
  7. Networking must be configured properly to ensure proper VMware Fault Tolerance functionality. Ensure each of the following is defined appropriately:
    • A separate VMkernel port group must be defined for Fault Tolerance logging. Instructions for creating this portgroup can be found in the Networking chapter of the ESX Configuration Guide.
    • Fault Tolerance logging and VMotion portgroups must be defined and assigned a physical network card for uplink. This network card must be at least 1Gb, with a 10Gb card preferred.
    • Enable use of Jumbo Frames for the Fault Tolerance logging. For detailed steps, see the Advanced Networking section of the ESX Configuration Guide.
    • VMware recommends enabling fully redundant NICs to ensure availability, though Fault Tolerance can function without it.
    • In environments with constrained bandwidth, network utilization can be lowered by following the instructions in Reducing FT logging traffic for disk read intensive workloads (1011965).
    • For virtual machines hosted on ESX 4 and ESX 4 Update 1, vmxnet3 is not a supported NIC if you want to enable Fault Tolerance. All other types of NICs are supported (for example, flexible, vmxnet2 and e1000). For more information, see Enabling Fault Tolerance on a virtual machine configured with a vmxnet3 vNIC fails (1013757).  
For more information about VMware Fault Tolerance, see VMware Fault Tolerance FAQ (1013428) .

Additional Information

Additional information regarding VMware Fault Tolerance can be found in the vSphere Availability Guide.

See Also

Request a Product Feature

To request a new product feature or to provide feedback on a VMware product, please visit the Request a Product Feature page.


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  • 16 Ratings