From what I have read in the VMware documentation, it looks like yes, ESXi Hardware Requirements . But do any of you in practice use a USB drive that has the ESXi server on it, but maybe the scratch drive on the local disk (or in the RAM)? It seems so foreign to me to put an OS on a flash drive, except in hobby type labs, but I think I am stuck in the olden days. What if the flash drive dies? Can you just put a new one in and install ESXi again and it mount the clustered datastore (or maybe you have a duplicate drive standing by).
I have local drives and iSCSI drives. My local drives are 500GB, but I don't want to put ESXi on those, if I can use them for a datastore (mirrored and backed up, etc.)