I have found and followed this document.
However, like I mention in my OP, I keep getting..
vSAN datastore can only upload VMDK files using the VMware stream optimized format.
which keeps preventing me to upload.
Again my specs are HCI VxRail using vSphere Client version 126.96.36.199000
Welcome to Communities, vSphere and vSAN.
Are you trying to upload it at the datastore level or to a folder created on the datastore? Files should always be uploaded to folders.
As a workaround can you test uploading this to a folder via the Host client (as opposed to the vSphere client) - open this via your browser using the management IP address or FQDN of any host in the cluster.
Alternatively, you should be able to do this by uploading this (to a folder/namespace) using a tool such as WinSCP.
Thanks for the reply,
I have been using the browser to access vsphere.
I have also created a folder called ISO to upload my guest ISOs but when I try to upload an ISO into said folder I get this prompt.(See attachment)
Yes I get the problem, but I don't think the way you are trying it will work - please if you can try the two workarounds I suggested.
A third workaround would be to upload the ISO to the VxRail service datastore via datastore browser and then simply us 'cp' or 'mv' to relocate it to a namespace folder on vsanDatastore via SSH