HP XP P9000 Continuous Access Synchronous for Mainframe Systems User Guide

CG See consistency group (CTG).
CH channel
channel adapter
(CHA)
The hardware component that processes channel commands from hosts and manages host access
to cache.
channel path The communication path between a channel and a control unit. A channel path consists of the
physical channel path and the logical path.
CHAP challenge handshake authentication protocol
CL cluster
CLI command line interface
CLPR cache logical partition
cluster Multiple-storage servers working together to respond to multiple read and write requests.
command device A dedicated logical volume used only by RAID Manager and Business Continuity Manager to
interface with the storage system. Can be shared by several hosts.
configuration
definition file
Defines the configuration, parameters, and options of RAID Manager operations. A text file that
defines the connected hosts and the volumes and groups known to the RAID Manager instance.
consistency group
(CG, CTG)
A group of pairs on which copy operations are performed simultaneously; the pairs’ status changes
at the same time. See also extended consistency group (EXCTG).
consistency time
(C/T)
Shows a time stamp to indicate how close the target volume is to the source volume. C/T also
shows the time stamp of a journal and extended consistency group.
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.
copy-on-write 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 copy-on-write
CTG See consistency group (CTG).
CTG See consistency group (CTG).
CTL controller
CU control unit
currency of data The synchronization of the volumes in a copy pair. When the data on the secondary volume
(S-VOL) is identical to the data on the primary volume (P-VOL), the data on the S-VOL is current.
When the data on the S-VOL is not identical to the data on the P-VOL, the data on the S-VOL is
not current.
CYL, cyl cylinder
cylinder bitmap Indicates the differential data (updated by write I/Os) in a volume of a split or suspended copy
pair. The primary and secondary volumes each have their own cylinder bitmap. When the pair
is resynchronized, the cylinder bitmaps are merged, and the differential data is copied to the
secondary volume.
DASD direct-access storage device
data consistency When the data on the secondary volume is identical to the data on the primary volume.
data path The physical paths used by primary storage systems to communicate with secondary storage
systems in a remote replication environment.
data pool One or more logical volumes designated to temporarily store original data. When a snapshot is
taken of a primary volume, the data pool is used if a data block in the primary volume is to be
176 Glossary