HP ProLiant 1500 SMART-2DH Array Controller Reference Guide - Page 170

Fault Tolerance and Drive Failure, A Non-Fault-Tolerant RAID 0 Logical Drive

Get HP ProLiant 1500 PDF manuals and user guides View all HP ProLiant 1500 manuals
Add to My Manuals
Save this manual to your list of manuals

Page 170 highlights

G-2 Recovering from Drive Failure Problems such as reduced system performance or disk errors reported by the operating system do not necessarily imply that a drive has or has not been failed. If drive failures or repeated errors are suspected, Compaq recommends that Drive Array Advanced Diagnostics be run on the system. Fault Tolerance and Drive Failure In the event of a drive failure, the condition of the logical drive will vary depending upon the fault tolerance method used. Since a single array of physical drives can contain multiple logical drives with differing fault tolerance methods, conditions of each logical drive on the same array are not necessarily the same. At any one time, if more drives are failed than the fault tolerance mode allows, fault tolerance is referred to as being "compromised" and the condition of the logical drive can be referred to as "failed." If a logical volume is "failed," all requests from the operating system will be rejected with "unrecoverable" errors. A Non-Fault-Tolerant (RAID 0) Logical Drive s Can sustain no drive failures. If any physical drive in the array is failed, the condition of all non-fault-tolerant logical drives in the same array will also be "failed." This is because data is striped across all drives in the array. A RAID 1 (Mirroring) Logical Drive s Can sustain multiple drive failures as long as failed drives are not mirrored to one another. s Will be in a "failed" condition if any two failed drives are mirrored to one another. s Will be in a "regenerating" condition if at least one drive is failed and no failed drives are mirrored to one another. s Will be in a "rebuilding" condition if a previously failed drive has been replaced and the replacement drive is rebuilding. The volume may also be in a "rebuilding" condition following a drive failure if a spare drive was previously assigned and is rebuilding. Writer: Pamela King Project: SMART-2DH Array Controller Reference Guide Comments: 295469-002 File Name: N-APPG.DOC Last Saved On: 2/27/98 12:09 PM COMPAQ CONFIDENTIAL - NEED TO KNOW REQUIRED

  • 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
  • 162
  • 163
  • 164
  • 165
  • 166
  • 167
  • 168
  • 169
  • 170
  • 171
  • 172
  • 173
  • 174
  • 175
  • 176
  • 177
  • 178
  • 179
  • 180
  • 181
  • 182
  • 183
  • 184
  • 185
  • 186
  • 187
  • 188
  • 189
  • 190
  • 191
  • 192
  • 193
  • 194
  • 195
  • 196
  • 197
  • 198
G-2
Recovering from Drive Failure
Writer: Pamela King
Project: SMART-2DH Array Controller Reference Guide
Comments: 295469-002
File Name: N-APPG.DOC
Last Saved On: 2/27/98 12:09 PM
COMPAQ CONFIDENTIAL - NEED TO KNOW REQUIRED
Problems such as reduced system performance or disk errors reported by the
operating system do not necessarily imply that a drive has or has not been
failed. If drive failures or repeated errors are suspected, Compaq recommends
that Drive Array Advanced Diagnostics be run on the system.
Fault Tolerance and Drive Failure
In the event of a drive failure, the condition of the logical drive will vary
depending upon the fault tolerance method used. Since a single array of
physical drives can contain multiple logical drives with differing fault
tolerance methods, conditions of each logical drive on the same array are not
necessarily the same. At any one time, if more drives are failed than the fault
tolerance mode allows, fault tolerance is referred to as being “compromised”
and the condition of the logical drive can be referred to as “failed.” If a logical
volume is “failed,” all requests from the operating system will be rejected
with “unrecoverable” errors.
A Non-Fault-Tolerant (RAID 0) Logical Drive
■
Can sustain no drive failures. If any physical drive in the array is
failed, the condition of all non-fault-tolerant logical drives in the same
array will also be “failed.” This is because data is striped across all
drives in the array.
A RAID 1 (Mirroring) Logical Drive
■
Can sustain multiple drive failures as long as failed drives are not
mirrored to one another.
■
Will be in a “failed” condition if any two failed drives are mirrored to
one another.
■
Will be in a “regenerating” condition if at least one drive is failed and
no failed drives are mirrored to one another.
■
Will be in a “rebuilding” condition if a previously failed drive has been
replaced and the replacement drive is rebuilding. The volume may also
be in a “rebuilding” condition following a drive failure if a spare drive
was previously assigned and is rebuilding.