So, now that Cisco is all up in fiber SAN switches, it seems like VSANs are a big deal. But, what is the use? I mean, I can understand why VLANs are useful on an IP network, but it never made sense to me on a SAN. I mean, you should already be doing zoning which limits your traffic to only be visible between the host and the storage devices its supposed to see. What else does it offer that I'm overlooking?