A virtual SAN appliance, also called a virtual storage appliance (VSA), is a software bundle that allows a storage manager to turn the unused storage capacity in his network's virtual servers into a storage area network (SAN). The SAN provides a pool of shared storage that can be accessed by the virtual servers as needed.
A virtual SAN appliance is most often downloaded as a software program that runs on a virtual machine (VM), but some storage hardware vendors are beginning to incorporate SAN appliances into their firmware. Depending on the vendor, a virtual SAN appliance might also be called a virtual storage network appliance, a virtual storage optimization appliance or simply a virtual storage appliance.
See also: virtual appliance