- Its BOSS-S1 so possible to delete and create 2x virtual disks as per your comment.
But in any case this will require the deletion of existing ESXi which is not ideal, so something that should be done first thing prior ESXi install.

Actually these are vSAN Ready Nodes so came with ESXi pre-installed now that I remember.
I wonder why these do not come pre-partitioned into 2x virtual disks knowing the vSAN requires a VMFS datastore?
Bottom line, adding a VMFS datastore via the BOSS Card might be possible but not straightforward in this case.