http://www.v-front.de/2012/02/quadstor-delivers-storage.html gives an introduction to quadstor storage virtualization. This article although old is still relevant. Users of the storage virtualization software will notice a different GUI, and many features found the present software missing. At the time of writing this article the only features available were thin provisioning, data deduplication and VAAI support. Features such as high availability, clustering, synchronous mirroring, storage pools were added much later.