Dell PowerEdge 4300 Dell PowerEdge 4300 Systems User's Guide - Page 148

David Patterson, Garth Gibson, and Randy

Get Dell PowerEdge 4300 PDF manuals and user guides View all Dell PowerEdge 4300 manuals
Add to My Manuals
Save this manual to your list of manuals

Page 148 highlights

MS-DOS-such as Windows-are able to put the computer into protected mode. capacity. See also mirroring, RAID 10, striping. Abbreviation for Personal System/2. Abbreviation for power-supply paralleling board. Abbreviation for polyvinyl chloride. Abbreviation for quarter-inch cartridge. RAID 4 is commonly called guarding. It uses data striping, like RAID 0, but adds a single, dedicated parity drive. The parity data stored on this drive can be used to recover data lost from a single failed drive. RAID 4 configurations write data slowly because parity data has to be generated and written to the parity drive, and the generation of the parity data frequently requires reading data from multiple physical drives. See also guarding and striping. Acronym for redundant arrays of independent disks. This phrase was introduced by David Patterson, Garth Gibson, and Randy Katz at the University of California at Berkeley in 1987. The goal of RAID is to use multiple small, inexpensive disk drives to provide high storage capacity and performance while maintaining or improving the reliability of the disk subsystem. Patterson, Gibson, and Katz described five different methods, which are known as RAID levels 1 through 5. Each level uses one or more extra drives to provide a means of recovering data lost when a disk fails, so that the effective failure rate of the whole disk subsystem becomes very low. RAID 0 is commonly called striping. This was not originally defined as a RAID level but has since come into popular use. In this array configuration, data is written sequentially across the available disks and no redundancy is provided. RAID 0 configurations provide very high performance but relatively low reliability. RAID 0 is the best choice when controller cards are duplexed. See also striping. RAID 1 is commonly called mirroring. RAID 1 also uses striping, so RAID 1 may be regarded as the mirroring of RAID 0 configurations. RAID 1 is the best choice in high-availability applications that require high performance or relatively low data RAID 5, like RAID 4, is commonly called guarding. RAID 5 is identical to RAID 4, except that the parity data is distributed evenly across all physical drives instead of a parity drive. In configurations using a large number of physical drives in which a large number of simultaneous small write operations are being performed, RAID 5 offers potentially higher performance than RAID 4. RAID 4 and RAID 5 configurations are appropriate in high-availability applications where performance is less critical or where high data capacity is required. See also guarding. RAID 10 is a mirroring technique in which data is duplicated across two identical RAID 0 arrays or hard-disk drives. All data on a physical drive in one array is duplicated, or mirrored, on a drive in the second array. Mirroring offers complete redundancy of data for greater data security. See also mirroring, RAID 1, and striping. Acronym for random-access memory. The computer's primary temporary storage area for program instructions and data. Each location in RAM is identified by a number called a memory address. Any information stored in RAM is lost when you turn off your computer. Acronym for random-access memory digital-to-analog converter. 12 Dell PowerEdge 4300 Systems User's Guide

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14
  • 15
  • 16
  • 17
  • 18
  • 19
  • 20
  • 21
  • 22
  • 23
  • 24
  • 25
  • 26
  • 27
  • 28
  • 29
  • 30
  • 31
  • 32
  • 33
  • 34
  • 35
  • 36
  • 37
  • 38
  • 39
  • 40
  • 41
  • 42
  • 43
  • 44
  • 45
  • 46
  • 47
  • 48
  • 49
  • 50
  • 51
  • 52
  • 53
  • 54
  • 55
  • 56
  • 57
  • 58
  • 59
  • 60
  • 61
  • 62
  • 63
  • 64
  • 65
  • 66
  • 67
  • 68
  • 69
  • 70
  • 71
  • 72
  • 73
  • 74
  • 75
  • 76
  • 77
  • 78
  • 79
  • 80
  • 81
  • 82
  • 83
  • 84
  • 85
  • 86
  • 87
  • 88
  • 89
  • 90
  • 91
  • 92
  • 93
  • 94
  • 95
  • 96
  • 97
  • 98
  • 99
  • 100
  • 101
  • 102
  • 103
  • 104
  • 105
  • 106
  • 107
  • 108
  • 109
  • 110
  • 111
  • 112
  • 113
  • 114
  • 115
  • 116
  • 117
  • 118
  • 119
  • 120
  • 121
  • 122
  • 123
  • 124
  • 125
  • 126
  • 127
  • 128
  • 129
  • 130
  • 131
  • 132
  • 133
  • 134
  • 135
  • 136
  • 137
  • 138
  • 139
  • 140
  • 141
  • 142
  • 143
  • 144
  • 145
  • 146
  • 147
  • 148
  • 149
  • 150
  • 151
  • 152
  • 153
  • 154
  • 155
  • 156
  • 157
  • 158
  • 159
  • 160
  • 161
12
Dell PowerEdge 4300 Systems User’s Guide
MS-DOS—such as Windows—are able to
put the computer into protected mode.
36»·
Abbreviation for Personal System/2.
363%
Abbreviation for power-supply paralleling
board.
39&
Abbreviation for polyvinyl chloride.
4,&
Abbreviation for quarter-inch cartridge.
5$,’
Acronym for redundant arrays of indepen-
dent disks. This phrase was introduced by
David Patterson, Garth Gibson, and Randy
Katz at the University of California at Ber-
keley in 1987. The goal of RAID is to use
multiple small, inexpensive disk drives to
provide high storage capacity and perfor-
mance while maintaining or improving the
reliability of the disk subsystem.
Patterson, Gibson, and Katz described
five different methods, which are known
as RAID levels 1 through 5. Each level
uses one or more extra drives to provide
a means of recovering data lost when a
disk fails, so that the effective failure rate
of the whole disk subsystem becomes
very low.
5$,’±¼
RAID 0 is commonly called
striping
. This
was not originally defined as a RAID level
but has since come into popular use. In
this array configuration, data is written
sequentially across the available disks and
no redundancy is provided. RAID 0 config-
urations provide very high performance
but relatively low reliability. RAID 0 is the
best choice when controller cards are du-
plexed. See also
striping
.
5$,’±´
RAID 1 is commonly called
mirroring
.
RAID 1 also uses striping, so RAID 1 may
be regarded as the mirroring of RAID 0
configurations. RAID 1 is the best choice
in high-availability applications that require
high performance or relatively low data
capacity. See also
mirroring
,
RAID 10
,
striping
.
5$,’±¹
RAID 4 is commonly called
guarding
. It
uses data striping, like RAID 0, but adds a
single, dedicated parity drive. The parity
data stored on this drive can be used to
recover data lost from a single failed drive.
RAID 4 configurations write data slowly
because parity data has to be generated
and written to the parity drive, and the
generation of the parity data frequently re-
quires reading data from multiple physical
drives. See also
guarding
and
striping
.
5$,’±º
RAID 5, like RAID 4, is commonly called
guarding
. RAID 5 is identical to RAID 4,
except that the parity data is distributed
evenly across all physical drives instead
of a parity drive. In configurations using a
large number of physical drives in which
a large number of simultaneous small
write operations are being performed,
RAID 5 offers potentially higher perfor-
mance than RAID 4. RAID 4 and RAID 5
configurations are appropriate in
high-availability applications where per-
formance is less critical or where high
data capacity is required. See also
guarding
.
5$,’±´¼
RAID 10 is a mirroring technique in which
data is duplicated across two identical
RAID 0 arrays or hard-disk drives. All data
on a physical drive in one array is duplicat-
ed, or
mirrored
, on a drive in the second
array. Mirroring offers complete redun-
dancy of data for greater data security.
See also
mirroring
,
RAID 1
, and
striping
.
5$0
Acronym for random-access memory.
The computer’s primary temporary stor-
age area for program instructions and
data. Each location in RAM is identified by
a number called a
memory address
. Any
information stored in RAM is lost when you
turn off your computer.
5$0’$&
Acronym for random-access memory
digital-to-analog converter.