Here is an article on this:
It also talks a bit about ATA over Ethernet (AoE) which is a "cheap"
way of doing SANs - cheap being a relative term.
I myself would rather use iSCSI as it runs over IP (and therefore
doesn't have to be on same segment). But AoE is still interesting as
WAND Network Research Group
Department of Computer Science
University of Waikato