IBM DCS3860, Installation, User'S, And Maintenance Manual

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array. See also array, redundant array of
independent disks (RAID) .
RAID set
See array .
RAM See random-access memory .
random-access memory (RAM)
A temporary storage location in which the
central processing unit (CPU) stores and
executes its processes. Contrast with
DASD .
RDAC
See redundant disk array controller .
read-only memory (ROM)
Memory in which stored data cannot be
changed by the user except under special
conditions.
recoverable virtual shared disk (RVSD)
A virtual shared disk on a server node
configured to provide continuous access
to data and file systems in a cluster.
redundant array of independent disks (RAID)
A collection of disk drives ( array ) that
appears as a single volume to the server,
which is fault tolerant through an
assigned method of data striping,
mirroring, or parity checking. Each array
is assigned a RAID level, which is a
specific number that refers to the method
used to achieve redundancy and fault
tolerance. See also
array, parity check,
mirroring, RAID level, striping .
redundant disk array controller (RDAC)
(1) In hardware, a redundant set of
controllers (either active/passive or
active/active). (2) In software, a layer that
manages the input/output (I/O) through
the active controller during normal
operation and transparently reroutes I/Os
to the other controller in the redundant
set if a controller or I/O path fails.
remote mirroring
Online, real-time replication of data
between storage systems that are
maintained on separate media. The
Enhanced Remote Mirror Option is a
DCS3860 premium feature that provides
support for remote mirroring. See also
Global Mirroring , Metro Mirroring .
ROM See read-only memory .
router A computer that determines the path of
network traffic flow. The path selection is
made from several paths based on
information obtained from specific
protocols, algorithms that attempt to
identify the shortest or best path, and
other criteria such as metrics or
protocol-specific destination addresses.
RVSD See recoverable virtual shared disk .
SAI See Storage Array Identifier .
SA Identifier
See Storage Array Identifier .
SAN
See storage area network .
SATA See serial ATA .
scope Defines a group of controllers by their
Internet Protocol (IP) addresses. A scope
must be created and defined so that
dynamic IP addresses can be assigned to
controllers on the network.
SCSI See small computer system interface .
segmented loop port (SL_port)
A port that allows division of a
fibre-channel private loop into multiple
segments. Each segment can pass frames
around as an independent loop and can
connect through the fabric to other
segments of the same loop.
sense data
(1) Data sent with a negative response,
indicating the reason for the response. (2)
Data describing an I/O error. Sense data
is presented to a host system in response
to a sense request command.
serial ATA
The standard for a high-speed alternative
to small computer system interface (SCSI)
hard drives. The SATA-1 standard is
equivalent in performance to a 10 000
RPM SCSI drive.
serial storage architecture (SSA)
An interface specification from IBM in
which devices are arranged in a ring
topology. SSA, which is compatible with
small computer system interface (SCSI)
devices, allows full-duplex packet
multiplexed serial data transfers at rates
of 20 Mbps in each direction.
server A functional hardware and software unit
that delivers shared resources to
workstation client units on a computer
network.
Glossary
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