Xsan combines RAID arrays into large, easy-to-expand volumes of storage that clients use like local disks, but which are actually shared over a high-speed Fibre Channel fabric or a Distributed LAN Client (DLC) connection. This guide describes how to set up and manage an Xsan storage area network (SAN). This guide also helps you migrate your existing Xsan 3 storage area network to the latest version, either Xsan 4 for Yosemite clients or 4.1 for El Capitan clients.