A virtual LAN, or a VLAN as it is often referred to, is a virtual network of servers that are not co-located like traditional servers. They could even be on different network segments, but they are bound together by software as if they are co-located on the same segment.
So when you are creating an iSCSI SAN, you can create the same efficiencies for a VLAN as you can for a co-located SAN and what you are really doing with the VLAN and iSCSI SAN is creating a virtual datacenter spread across the network cloud. With a VLAN, you still need to separate your storage traffic from your regular network traffic, but it becomes your virtual datacenter.
Check out the entire iSCSI SAN FAQ.
This was first published in May 2008