GLYPH<SM590000> Facilitates a common platform for data replication, even if the back-end storage does not  have this functionality. GLYPH<SM590000> Provides a centralized point of control for storage provisioning across heterogeneous  SAN environments. GLYPH<SM590000> Reduces license costs for advanced functions in the virtualized storage systems. GLYPH<SM590000> Increases storage administrator productivity. GLYPH<SM590000> SAN Volume Controller GLYPH<SM590000> Storwize V7000 GLYPH<SM590000> Storwize V7000 Unified GLYPH<SM590000> Storwize V3700 and Storwize V5000 (For details, see 9.2, “General considerations:  V3700, V5000, and V7000” on page 127.) The following IBM products provide this technology: SAN Volume Controller can virtualize multi-vendor storage disks to perform LUN provisioning  in a high-end environment. In addition to performing external storage virtualization, Storwize  V7000 has internal disks that constitute its storage capacity for a mid-range environment.  Storwize V7000 Unified consolidates block (SAN) virtualization and file workloads  (network-attached storage, or NAS) into a single storage system. Supported vendor storage:  A list of supported vendor storage disks for SAN Volume  Controller is at the following web page:  http://www.ibm.com/support/docview.wss?uid=ssg1S1003658 Also see the IBM System Storage Interoperation Center (SSIC) website: http://www.ibm.com/systems/support/storage/ssic/interoperability.wss This section describes the terminology used in this chapter that relates to storage  virtualization. The following list includes the terms:  Storage pool Also known as managed disk group (MDG). An MDG is a collection  of storage capacity (MDisks) that provides the capacity  requirements (extents) for volumes that are based on MDisks  characteristics, such as disk speed and type. Managed disk (MDisk) An MDisk is composed of a Small Computer System Interface  (SCSI) logical unit (LU) that a Redundant Array of Independent  Disks (RAID) controller provides and that a clustered system  manages. The MDisk is not visible to host systems on the SAN. Volume/(VDisk) Also known as virtual disk (VDisk). A volume is the representation  of a SCSI disk that is presented to a host system.  Extents A unit of data that manages the mapping of data between managed  disks (MDisks) and volumes. By default, its size is 256 MB.  146  IBM ProtecTIER Implementation and Best Practices Guide 9.3.2 Terminology