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Changes to Fault Tolerance in vSphere 4.1 (1022844)

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This article describes the changes to Fault Tolerance (FT) in vSphere 4.1.


In vSphere 4.1:
  • FT is integrated with DRS, which means that DRS can now load balance both the primary and secondary Fault Tolerant virtual machines. 

    Note: This feature does require EVC.

  • FT has a version associated with it, which means that the primary and secondary ESX do not need to be run at the same build number/patch level.
  • Primary and secondary events are labelled as primary and secondary, which provides better differentiation
  • FT has improved host management. For example:
    • Moving ESX hosts from one vCenter Server  instance to another no longer causes FT failures
    • DRS can now vMotion FT protected virtual machines.
    • Administrators are now warned that FT is disabled when disabling HA. 
FT with vSphere 4.1 cannot function with these configurations:
  • Thin Provisioning and Linked Clones
  • Hot plug devices and USB Passthrough
  • IPv6 (HA does not support IPv6)
  • vSMP
  • N-Port ID Virtualization (NPIV)
  • Storage vMotion
  • Serial/parallel ports
  • Physical and remote CD/floppy drives

For more information on using Fault Tolerance, see the vSphere Availability Guide.

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