VMFS-5 Compatible with ESXi 4.1?

[nmanm0305]

Im currently upgrading my production environment to ESXi 6.7u1 (from 6.5).

I have a legacy, standalone, development host running ESXi 4.1 with VMFS-3 datastores.

I understand that vSphere 6.7 no longer supports VMFS-3 datastores. If a ESXi 6.7 host mounts a VMFS-3 datastore, the datastore will be automatically upgraded to VMFS-5.

Migration of the legacy host's VMs to the production cluster is currently not possible due to a networking limitation (subnet availability). Changing IP addresses of the VMs in the legacy environment is not an option. This limitation will soon be eliminated after implementation of Cisco ACI.

My question is......

Once the networking limitation is eliminated, will my legacy ESXi 4.1 host be able to mount the VMFS-5 datastores (in the 6.7 environment)?

[cjscol · Accepted solution]

ESXi 4.1 does not support VMFS 5, you will need VMFS 3 (or 2) datastores for the ESXi 4.1 host(s).

[continuum]

>Once the networking limitation is eliminated, will my legacy ESXi 4.1 host be able to mount the VMFS-5 datastores (in the 6.7 environment)?
NO
> Migration of the legacy host's VMs to the production cluster is currently not possible due to a networking limitation (subnet availability).
I doubt that !
As soon as you can use a Linux VM to ping both the old ESXi and one of the new ones you can migrate the VMs.
Inside the Linux VM do this
mkdir /vmfs-in
mkdir /vmfs-out
sshfs -o ro root@oldESXI:/vmfs/volumes/source-datastore/ /vmfs-in
sshfs root@newESXi:/vmfs/volumes/target-datastore/ /vmfs-out
Now you can copy your VMs from /vmfs-in to /vmfs-out.
I recommend to use cp for the small files and ddrescue for all the larger flat and delta.vmdks
Of course this is not the fastest approach - but it is  a very very reliable one. It can even handle network dropouts along the way.