▪A Virtualizing Controller can virtualize (some or all) volumes from any Back-end Storage System, but nothing else. This rule means that there can be only one level of virtualization. You cannot virtualize a Virtualizing Controller or build a “virtualization circle.” Furthermore, systems at the same level cannot virtualize each other.

▪An SVC operates by default as a Virtualizing Controller, and this cannot be changed. Thus an SVC acts by default as a virtualizing system and cannot become virtualized.

▪An IBM Storage Virtualize system operates by default as the back-end storage system. The 9500, 9200, 9100, 7300, 7200, 5200, 5100, 5000, V7000 and V5100 can become a Virtualizing Controller and then virtualize other systems. The V5000E models remain always as the back-end storage system and can never act as Virtualizing Controllers.

▪Systems from other storage families including non-IBM are always back-end storage systems and can be virtualized by Virtualizing Controllers.

▪Volumes in a Virtualizing Controller regular pool can be fully allocated or thin-provisioned.

▪Volumes in a Virtualizing Controller DRP can be fully allocated, thin-provisioned only, compressed without deduplication, deduplicated without compression, or deduplicated and compressed. (Compression and deduplication include always thin provisioning.)

▪At the Back-end Storage System, external MDisks can do their own data reduction. Such MDisks present to the pool in a Virtualizing Controller a logical capacity that can be a multiple of their usable capacity.