HP StorageWorks 4000/6000/8000 Enterprise Virtual Array Updating Product Software Guide XCS 5.031 (5697-5541, December 2005)

virtual disk. Up to seven snapshots of a n active virtual disk can exist at any
point. The active disk and its snapshot c onstitute a virtual family.
storage system
software
The storage system software consists of XCS and EMU firmware.
termination event An occurrences that causes the storage system to cease operation.
uninitialized sys-
tem
A state in which the storage system is not ready for use.
See also initialization.
XCS Virtual Controller Software. Provides storage controller software capabilit y for
the HSV controller.
Vdisk Virtual Disk. A simulated disk drive created by the controllers as storage
for one or more hosts. The virtual disk characteristics, chosen by the storage
administrator, provide a specific combination of capacity, availability,
performance, and accessibility. A controller pair simulates the characteristics
of the virtual disk by deploying the disk group from which the virtual disk was
created. The h ost computer sees the virtual disk as “real,” with the characteristics
of an identical physical disk.
virtual disk family A grouping that c onsists of a virtual disk and its snapshot, if a snapshot exists.
The original virtual disk is called the active disk. When you firstcreateavirtual
disk family, the only member is the active disk.
Vraid0 A virtualization technique that provides no data protection. A data host is
broken down into chunks and distributed on the disks comprising the disk g roup
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 twice on separate phys ical disks. For
read requests, the block can be read from either disk, which can increase
performance. Mirroring takes 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. Parity i s a data protection mechanism for a striped virtual disk. A
striped virtual disk is one where the data to and from the host is broken down
into chunks and distributed on the physical disks comprising the disk group in
which the virtual disk was created. If the striped virtual disk has parity, another
chunk (a parity chunk) is calculated from the set of data chunks a nd written to
the physical disks. If one of the data chunks becomes c orrupted, the data can
be reconstructed from the parity chunk and the remaining data chunks.
WWN World Wide Name. A unique Fibre Channel identifier consisting of a
16-chara cter hexadecimal number. A WWN is required for each Fibre Channel
communication port.
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Glossary