4 Implementing the IBM Storwize V7000 with IBM Spectrum Virtualize V8.2.1
Storage virtualization allows us to manage the mapping between logical blocks within an LU 
presented to a host, and blocks on physical drives. This mapping can be as simple, or as 
complicated, as required by a given use case. A logical block can be mapped to one physical 
block or for increased availability, multiple blocks that are physically stored on different 
physical storage systems, possibly in different geographical locations. 
Importantly, the mapping can be dynamic: with EasyTier functionality, IBM Spectrum 
Virtualize can automatically change underlying storage, to which given groups of blocks 
(extent) are mapped, to better match a host’s performance requirements with the capabilities 
of the underlying storage systems. 
IBM Spectrum Virtualize gives a storage administrator a wide range of options to modify 
volume characteristics: from volume resize, to mirroring, to creating a point-in-time copy with 
IBM FlashCopy®, to migrating data across physical storage systems. Importantly, all the 
functionality that is presented to the storage consumers is independent from characteristics of 
the physical devices that are used to store data. This decoupling of the storage feature set 
from the underlying hardware and ability to present a single, uniform interface to storage 
users that masks underlying system complexity is a powerful argument for adopting storage 
virtualization with IBM Spectrum Virtualize.
Storage virtualization can, and is, being implemented on many layers. Figure 1-2 on page 3 
shows an example where a file system block gets mirrored by the host’s operating system (left 
side of the figure) by using features of the logical volume manager (LVM), or by IBM Spectrum 
Virtualize system at the storage pool level (as shown on the right side of Figure 1-2 on 
page 3). Although the result is similar (the data block is written to two different arrays), the 
effort that is required for per-host configuration is disproportionately larger than for a 
centralized solution with organization-wide storage virtualization that is done on a dedicated 
system and managed from a single GUI. 
IBM Spectrum Virtualize includes the following key features: 
/SM590000Simplified storage management by providing a single management interface for multiple 
storage systems, and a consistent user interface for provisioning heterogeneous storage.
/SM590000Online volume migration. IBM Spectrum Virtualize enables moving the data from one set 
of physical drives to another, in a way that is transparent for the storage consumers and 
without over-straining the storage infrastructure. The migration can be done within a 
specific storage system (from one set of disks to another), or across storage systems. 
Either way, the host that uses the storage is not aware of the operation, and no downtime 
for applications is needed.
/SM590000Enterprise-level Copy Services functions. Performing Copy Services functions within the 
IBM Spectrum Virtualize removes dependencies on capabilities and intercompatibility of 
the virtualized storage subsystems. Therefore, it enables the source and target copies to 
be on any two virtualized storage subsystems.
/SM590000Improved storage space usage because of pooling of resources across virtualized storage 
systems.
/SM590000Opportunity to improve system performance as a result of volume striping across multiple 
virtualized arrays or controllers and the benefits of cache that is provided by IBM 
Spectrum Virtualize hardware.
/SM590000Improved data security by way of data-at-rest encryption.
/SM590000Data replication, including replication to cloud storage by using advanced copy services 
for data migration and backup solutions.