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baber
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FT Limitation

i read below limits about FT:

1 - The maximum number of fault tolerance vms allowed on a host in the cluster Both primary vms and secondary vms count towards this limit .the default value is 4

Is that means maximum vm that can FT protected on an esxi host is 4vms with 1vcpu?

2- Maximum number of vcpu aggregated across all fault tolerance vms on a host vcpu from both primary vms and secondary vms count toward this limit . The default value is 8

Is that means when we enable FT protected on vm1 that ave 4vcpu that's shadow (secondary vm) will be create on the other host with 4vcpu

Are my imagine from FT correct ?

BR

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a_p_
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imagine i have 3 host in my cluster if i protect 2vms on host1 and 2 vms on host and 2 vms on host3 in this mode maximums are reached and can not enable FT for the other vms

is that correct ?

Yes, but keep in mind that if a host fails, FT won't  be able to create another secondary for failed over VMs, i.e. the failed over VMs will run without protection.

is this vmware best practice that if want enable FT on a vm use minimum 3 hosts ?

It's the recommendation. Again FT is usually used to protect VMs which need to be highly available.

Conclusion: Make sure that you do have sufficient free resources to create new secondary VMs for failed over VMs in case of a host failure

André

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baber
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so thanks

this is my Conclusion : in vmware document maximum configuration for FT on  per host = 4 vms actually wen can FT on 2 vms on each host 4vms here means (2 primary vms+2 secondary vms)

is that correct ?

BR

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baber
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now in vsphere 6.7 this is for max configuration FT

22.jpg

in esxi 6.7 i can run one type of these scenarios in my cluster with 6 esxi hosts :

1- according to vmware configuration i can run maximum 4 vms on each host thereby i can run 24vms in my cluster (12primary vms + 12 secondary vms ) infact can run 12vms in my cluster

2- according to vmware max configuration , maximum vcpu that i can use in my cluster with 6 host is 48vcpu but actually (24vcpu for primary vm and 24vcpu for secondary vm )

is that correct ?

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a_p_
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Yes, that's how I understand this too. Always take primary, and secondary into account.

None of the configuration maximums must be exceeded at any time.

André

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