Virtual storage is the pooling of physical storage from multiple network storage devices into what appears to be a single storage device that is managed from a central console.
Storage virtualization software converts a server, typically an X86 server, into a storage controller and the storage inside the server into the storage system. The benefit of virtualization is that commodity hardware or less-expensive storage can be used to provide enterprise-class functionality. Storage virtualization also helps the storage administrator perform the tasks of backup, archiving, and recovery more easily -- and in less time -- by disguising the actual complexity of a storage area network (SAN).
Enterprise virtual storage products include Hitachi Data Systems’ Virtual Storage Platform (VSP), IBM SAN Volume Controller (SVC) and NetApp V-Series. Software-based virtual storage appliances such as HP's Lefthand or DataCore Software's SANsymphony are also options for provisioning and working with virtual storage.