Dell 6 series, User Manual

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Glossary
Disk Array
A collection of disks from one or more disk subsystems combined using a
configuration utility. The utility
controls the disks and presents them to the
array operating environment as one or more logical drives.
Disk Group
A logical grouping of disks attached to a RAID controller on which one or more
virtual disks can be created, such that all virtual disks in the disk group use all of
the physical disks in the disk group.
Disk Migration
Moving a virtual disk or a hot spare from one controller to another by detaching
the physical disks and re-attaching them to the new controller.
Disk Roaming
Moving disks from one slot to another on a controller.
Disk Subsystem
A collection of disks and the hardware that controls them and connects them to
one or more controllers. The hardware can include an intelligent controller, or
the disks can attach directly to a system I/O bus controller.
Distributed Parity
Parity involves an extra bit added to a byte or word to reveal errors in storage (in
RAM or disk) or transmission. Parity is used to generate a set of redundancy data
from two or more parent data sets. The redundancy data can be used to rebuild
one of the parent data sets. In distributed parity, the parity data are distributed
among all the physical disks in the system. If a single physical disk fails, it can be
rebuilt from the parity of the applicable data on the remaining physical disks.
Dell_PERC6.2_UG.book Page 140 Wednesday, June 24, 2009 6:08 PM