Testing vSphere FT on unsupported processors (even in nested mode!)

0 Flares Twitter 0 Facebook 0 LinkedIn 0 Email -- 0 Flares ×

This is a guest post by Massimiliano Moschini, recentyl awarded vExpert 2012!

For those who want to test vSphere FT (Fault Tolerance) but does not have supported processors (have a look at the supported processors in KB 1008027), or if you have a lab made with nested ESXi, yes is it possible to force FT activation.
Disclaimer: thismode is NOT supported and absolutely deprecated in production environments, but is only for test purposes, also there are some problems and unstability. For example FT may not reactivate after a host crash, or sometimes secondary VM is not recreated after the original secondary has become primary.

Anyway, this is what you need to do:

– shutdown the VM
– go to Edit Settings – Options Tab – Advanced/General
– select Configuration Parameters
– add these three new lines with the listed parameters:
Name=replay.allowFT Value=true
Name=replay.allowBTOnly Value=true
Name=replay.supported Value=true
– Save and exit

At this point you will be able to enable FT logging on a VMkernel port on the hosts of the HA cluster, and do your tests.
Enjoy yourselves!

PS: if you are thinking about trying this on a multi-processor VM, forget about it. I already tried it and is not going to work 😉