Mainframe Storage Virtualization Extends Its Reach

by Fred Moore
June 23, 2009

Virtual disk array capabilities let you:

• Create up to 32 (current) different virtual storage machines or flexible system Logical Partitions (LPARs) within a disk subsystem

• Dedicate cache, ports, back-end resource aggregation and consolidation for specific applications

• Consolidate heterogeneous storage systems and environments

• Dynamically re-allocate resources between virtual storage machines to meet changing workloads.

Integrated virtual tape (disk array and tape library) capabilities let you:

• Integrate a disk array and physical tape library. The disk array serves as cache buffer for more active data providing disk-like recall times for most accesses. As the data transparently migrates from disk to the physical tape, the logical volumes are stacked on each tape cartridge to improve utilization; typically achieving 80 percent or more utilization per cartridge.

• Decrease the number of physical tape drives as many I/O requests are serviced from the buffer

• Decrease the amount of tape media as a result of stacking multiple virtual tape volumes on a tape cartridge

• Support de-duplication and local and remote backup locations

• Support open systems

• Integrate Tier 2 (backup) and Tier 3 (long-term storage, compliance and archive) technologies into a common platform.

Virtual tape (disk only, no physical tapes) capabilities let you:

• Use a VTL, which is a disk array virtualized to appear to the operating system as tape drives and library (no physical tapes or library)

• Improve performance for the backup and recovery application because a tape mount isn’t required

• Leave existing backup software procedures intact, simplifying implementation

• Support de-duplication and local and remote backup locations via VTLs

• Use host-based virtual tape (because disk-only VTL is just emerging for mainframes).

Storage Virtualization Extends to Open Systems

Consider the open system’s evolution into virtualized storage, which essentially lagged that of the mainframe for well over a decade. For open systems, storage virtualization capabilities started on the operating system, where most of the control points were located for UNIX, Windows, and later Linux. SAN and Network-Attached Storage (NAS) have been a major initiative for more than a decade and ultimately moved much open systems storage virtualization off the server.

By 2002, the virtual tape market for open systems was gaining some momentum as a backup solution. By 2005, virtual tape, combined with de-duplication, became a popular storage initiative for many open systems storage management systems. Open systems businesses have countless, non-integrated storage management products to choose from, and storage software vendors are working to reduce the complexity and number of choices.