FT VM on VSAN

[vmb01]

Hi,

I'm using Fault Tolarenace with legacy storage , creating the secondary VM means to create a new VM folder containing a copy of all the VMX, VMK and so on.

If my primary VM is in a VSAN datastorem,  deployed with FTT=1, I already have a replica of the files.

Enabling FT mean to create a second pair of files ?

[Ryanware]

Hi

FT=1 on VSAN Mean you have  one  sync r of replica, just like Hardware Raid 1  ,

So if you have another replica of a clone of your vms , you can say you have two copy of the one VM but VSAN replica is always sync, if you loose the any of the Vm or replica , things will continue without any issue

Alex

[vmb01]

Thanks,

I do not have a replica or a clone of my VM, I''m enabling Fault tolerance so I have a secondary VM .

[Ryanware]

As far as i know, with you cannot enable FT with FTT=1  because of latency issue, if you make the FTT=0 on VSAn policy then I belive Fault tolerance(FT)  also supported

[TheBobkin · Accepted solution]

Hello vmb01​,

"If my primary VM is in a VSAN datastorem,  deployed with FTT=1, I already have a replica of the files.

Enabling FT mean to create a second pair of files ?"

Yes, this works when stored on vsanDatastore the same as it does on SAN in that there are two sets of the VMs files (namespace folder, .vswp + .vmdk(s)).

Do note that having primary and secondary on a mix of vSAN and and non-vSAN storage is not supported:

Best Practices for Fault Tolerance

Ryanware , actually we advise using FTT=1 over FTT=0 for FT VMs to ensure accessibility, Cormac covered this well:

https://cormachogan.com/2018/06/06/a-deeper-dive-in-fault-tolerant-vms-running-on-vsan/

Perhaps you are thinking of Stretched-Cluster support:

https://cormachogan.com/2017/09/26/supporting-fault-tolerance-vms-vsan-stretched-cluster/

Bob