Storage Virtualization
Subsystem-Based Virtualization
Subsystem-Based Virtualization
Disk storage
Advantages
capacity allocated
to individual hosts
• Proven technology
• Spread out data across
many disks—improves
performance
• Supports any file system
or OS
Disadvantages
• Vendor-specific
• Capacity usually
Virtualization in
Disk subsystem
allocated per storage
device (with some
high-end exceptions)
Virtual Storage Pools
In this implementation, the virtualization software resides in the firmware of the
storage devices, presenting a logical view of a single storage pool to the
server. Many subsystem vendors offer proprietary virtualization within, and
sometimes even between, their subsystems.
This implementation may be desirable where:
Hosts are heterogeneous
Storage devices are homogeneous
Cost is a primary concern