Hitachi VSP F400, System Administration Manual, Page: 389 / 414

cluster
Multiple-storage servers working together to respond to multiple read and
write requests.
command device
A dedicated logical volume used only by Command Control Interface and
Business Continuity Manager to interface with the storage system. Can be
shared by several hosts.
controller
The component in a storage system that manages all storage functions. It
is analogous to a computer and contains a processors, I/O devices, RAM,
power supplies, cooling fans, and other sub-components as needed to
support the operation of the storage system.
copy pair
A pair of volumes in which one volume contains original data and the
other volume contains the copy of the original. Copy operations can be
synchronous or asynchronous, and the volumes of the copy pair can be
located in the same storage system (local copy) or in different storage
systems (remote copy).
A copy pair can also be called a volume pair, or just pair. A pair created by
Compatible FlashCopy
® is called a relationship.
copy-on-write (COW)
Point-in-time snapshot copy of any data volume within a storage system.
Copy-on-write snapshots only store changed data blocks, therefore the
amount of storage capacity required for each copy is substantially smaller
than the source volume.
COW
See copy-on-write (COW) .
COW Snapshot
Hitachi Copy-on-Write Snapshot
custom volume (CV)
A custom-size volume whose size is defined by the user using Virtual LVI/
Virtual LUN.
Glossary 389
System Administrator Guide for VSP Gx00 models and VSP Fx00 models