HP StorageWorks Continuous Access EVA Administrator Guide (T3687-96043, December 2005)

source–destina-
tion pair
Acopyset.
Storage Manage-
ment Appliance
HP OpenView Storage Management Appliance, an HP hardware–software
product designed to run SAN management applications such as HP
Storage Works Com
mand View EVA a nd HP StorageWorks Replication Solutions
Manager.
storage system Synonymous with virtual array. The H P StorageWorks Enterprise Virtual Array
consists of one or more storage systems. See also virtual array.
synchronous A descriptive term for computing mod els that perform tasks in chronological
order without interruption. In synchronous replication, the source waits for da ta
to be copied at the d
estination before acknowledging that it h as been written at
the source. See also asynchronous.
UUID Unique Universal Identifier, a unique 128–bit identifier for each component of
an a rray. UUIDs ar
e internal system values that users cannot modify.
VCS Virtual Controller Software. The software in H P StorageWorks Enterprise Virtual
Array controllers on specific models. Controller software manages all aspects of
array operation, including communication with HP StorageWorks Command
View EVA. See als
o XCS.
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 disks.
Virtual Con trolle
r
Software
See VCS.
virtual disk Variable disk capacity that is defined and managed by the array controller
and presentable to hosts as a disk.
Vraid Techniques for configuring virtual disks to provide fault tolerance and increase
performance. Vraid techniques are identified by level numbers.
Level Redundancy Technique
Vraid0 None Striping
Vraid1 High Mirroring
Vraid5 Medium Striping and parity
Vraid0 A virtualization technique that provides no data protection. Data chunks are
distributed across the disk group from which the virtual disk is created. Reading
and writing to a Vraid0 virtual disk is very fast and uses available storage to the
fullest, but provides no data p rotection (redundancy) unless there is parity.
Vraid1 A virtualization technique that provides the highest level of data protection. All
data blocks are mirrore d
, or written twice, on separate disks. For read requests,
the block c an 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 a mount 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 re constructed from the parity
chunk and the remaining data chunks.
XCS The software in H P Stora geWorks Enterprise Virtual Array controllers on specific
models. Controller software manages all aspects of array operation, including
communication with HP StorageWorks Command View EVA. See also VCS.
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