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Glossary
system. The PERC Virtual Disk Management utility, accessed by pressing
<Ctrl><R> at system startup, is built on elements called controls. Each control
performs a function. The functions include procedures you can use to configure
physical disks and virtual disks. The PERC Virtual Disk Management utility differs
from the Dell Inc. system BIOS, which contains the BIOS settings for each Dell
platform and is accessed by pressing <F2> during system startup.
P
HYSICAL
D
ISK
— A non-volatile, randomly-addressable device for storing data.
Physical disks are rewriteable and commonly referred to as disk drives.
P
N
P (P
LUG
AND
P
LAY
)—A technology that allows automatic recognition of
interface cards and devices when plugged into a PC.
P
ORT
— A connection point to a RAID controller, disk drive, enclosure, or another
device.
RAID (R
EDUNDANT
A
RRAY
OF
I
NDEPENDENT
D
ISKS
)—An array of multiple
independent physical disks managed together to yield higher reliability and/or
performance exceeding that of a single physical disk. The virtual disk appears to the
operating system as a single storage unit. I/O is expedited because several disks can be
accessed simultaneously. Redundant RAID levels (RAID levels 1, 5, and 10) provide
data protection.
RAID L
EVELS
— A set of techniques applied to the physical disks in a virtual disk to
deliver higher data availability, and/or performance characteristics to host
environments. Each virtual disk must have a RAID level assigned to it.
RAID M
ANAGEMENT
U
TILITY
— A RAID management utility (PERC Virtual Disk
Management utility) is used to configure physical disks and virtual disks. Use the
PERC Virtual Disk Management utility if the operating system has not yet been
installed on the controller.
R
EBUILD
— The regeneration of all data to a replacement disk in a redundant virtual
disk (RAID levels 1, 5, and 10) after a physical disk failure. A disk rebuild normally
occurs without interrupting normal operations on the affected virtual disk, though
some degradation of performance of the disk subsystem can occur.
R
EDUNDANCY
— The provision of multiple interchangeable components to perform
a single function to cope with failures and errors. Common forms of hardware
redundancy are disk mirroring, implementations of parity disks, or distributed parity.
R
EDUNDANT
V
IRTUAL
D
ISK
— A redundant virtual disk is one which has redundant
data on physical disks that can be used to rebuild a failed physical disk. A virtual disk
can use disk striping across the physical disks, disk mirroring or parity to provide
redundancy. This offers protection in case of a physical disk failure.
R
EPLACEMENT
D
ISK
— A physical disk that replaces a failed physical disk in a virtual
disk.
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