HP P6000 Replication Solutions Manager User Guide (T3680-96089, October 2012)

snapclone A copy that begins as a fully allocated snapshot and becomes an independent virtual disk. Applies
only to the HP Enterprise Virtual Array.
snapshot A nearly instantaneous copy of the contents of a virtual disk created without interruption of
operations on the source virtual disk. Snapshots are typically used for short-term tasks such as
backups.
source The virtual disk, DR group, or virtual array where I/O is stored before replication. See also
destination.
source-destination
pair
A copy set.
SPOF Single point of failure.
standby
management
server
A backup management server. See management server.
storage system A system consisting of one or more arrays; synonymous with virtual array. See also array.
synchronous Describes computing models that perform tasks in chronological order without interruption. In
synchronous replication, the source waits for data to be copied at the destination before
acknowledging that it has been written at the source.
V
virtual array Synonymous with disk array and storage system; a group of disks in one or more disk enclosures
combined with control software that presents disk storage capacity as one or more virtual disks.
See also virtual disk.
Virtual Controller
Software (VCS)
See controller software.
virtual disk Variable disk capacity that is defined and managed by the array controller and presented to
hosts as a disk. May be called Vdisk in the user interface.
Vraid The level to which user data is protected. Redundancy is directly proportional to cost in terms of
storage usage; the greater the level of data protection, the more storage space is required. See
also: Vraid0, Vraid1, Vraid5, Vraid6.
Vraid0 A virtualization technique that provides no data protection. The data host is broken down into
chunks and distributed on the disks comprising the disk group from which the virtual disk was
created. Reading and writing to a Vraid0 virtual disk is very fast and makes the fullest use of the
available storage, but there is no data protection (redundancy) unless there is parity.
Vraid1 A virtualization technique that provides the highest level of data protection. All data blocks are
mirrored, or written on two separate disks. For read requests, the block can be read from either
disk, which can increase performance. Mirroring requires the most storage space because twice
the storage capacity must be allocated for a given amount of data.
Vraid5 A virtualization technique that uses parity striping to provide moderate data protection. For a
striped virtual disk, data is broken into chunks and distributed across the disk group. If the striped
virtual disk has parity, another chunk (a parity chunk) is calculated from the data chunks and
written to the disks. If a data chunk becomes corrupted, the data can be reconstructed from the
parity chunk and the remaining data chunks.
Vraid6 Offers the features of Vraid5 while providing more protection for an additional drive failure, but
uses additional physical disk space.
W
WDM Wavelength division multiplexing. The technique of placing multiple optical signals on a single
optical cable simultaneously.
write history log A dedicated area of disk capacity used to record host write I/O to the source virtual disks.
X
XCS See controller software.
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