1. A storage arrangement comprising a first storage system comprising a first physical storage space constituted by a first plurality of physical storage devices controlled by one or more first storage control devices constituting a first control layer, and one or more second storage systems operatively coupled to the first storage system and each comprising a second physical storage space constituted by a second plurality of physical storage devices controlled by one or more second storage control devices constituting a second control layer; wherein the first control layer is operable to handle a first logical address space comprising at least one first logical group characterized by a plurality of logical block addresses; wherein said first control layer comprises a first mapping module handling a first mapping structure associated with said at least one first logical group; wherein each said second control layer comprises, respectively, a second mapping module handling a second mapping structure associated with said at least one first logical group; and wherein the first mapping structure is configured to provide mapping between logical addresses related to said at least one first logical group and corresponding addresses related to the first physical address spaces, and/or to point to respective second mapping structure configured to provide mapping between logical addresses related to said at least one first logical group and corresponding addresses related to respective second physical address spaces.