HP StorageWorks 6100 - Enterprise Virtual Array User Manual page 220

preferred path A preference for which controller of the controller pair manages the virtual disk.
This preference is set by the user when creating the virtual disk. A host can
change the preferred path of a virtual disk at any time. The primary purpose of
preferring a path is load balancing.
protocol The conventions or rules for the format and timing of messages sent and received.
pushbutton A button that is engaged or disengaged when it is pressed.
quiesce The act of rendering bus activity inactive or dormant. For example, "quiesce the
SCSI bus operations during a device warm-swap."
rack A floorstanding structure primarily designed for, and capable of, holding and
supporting storage system equipment. All racks provide for the mounting of panels
per Electronic Industries Alliance (EIA) Standard RS310C.
rack-mounting unit A measurement for rack heights based upon a repeating hole pattern. It is
expressed as "U" spacing or panel heights. Repeating hole patterns are spaced
every 1.75 inches (44.45 mm) and based on EIA's Standard RS310C. For
example, a 3U unit is 5.25inches (133.35 mm) high, and a 4U unit is 7.0inches
(177.79 mm) high.
read caching
A cache method used to decrease subsystem response times to a read request
by allowing the controller to satisfy the request from the cache memory rather
than from the disk drives. Reading data from cache memory is faster than reading
data from a disk. The read cache is specified as either On or Off for each virtual
disk. The default state is on.
read ahead A cache management method used to decrease the subsystem response time to
caching a read request by allowing the controller to satisfy the request from the cache
memory rather than from the disk drives.
reconstruction The process of regenerating the contents of a failed member data. The
reconstruction process writes the data to a spare set disk and incorporates the
spare set disk into the mirrorset, striped mirrorset or RAID set from which the
failed member came.
red wine-colored A convention of applying the color of red wine to a CRU tab, lever, or handle
to identify the unit as hot-pluggable.
redundancy 1.
2.
redundant power
A capability of the Enterprise storage system racks and enclosures to allow
configuration continuous system operation by preventing single points of power failure.
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220 Glossary
Element Redundancy—The degree to which logical or physical elements are
protected by having another element that can take over in case of failure.
For example, each loop of a device-side loop pair normally works independ-
ently but can take over for the other in case of failure.
Data Redundancy—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.
For a rack, two AC power sources and two power conditioning units distribute
primary and redundant AC power to enclosure power supplies.
For a controller or drive enclosure, two power supplies ensure that the DC
power is available even when there is a failure of one supply, one AC source,
or one power conditioning unit. Implementing the redundant power configur-
ation provides protection against the loss or corruption of data.