HP 6100 HP 4x00/6x00/8x00 Enterprise Virtual Array User Guide (5697-0733, Marc - Page 177

SCSI-3 Enclosure, redundant power

Page 177 highlights

read ahead caching read caching reconstruction redundancy redundant power configuration reporting group room temperature A cache management method used to decrease the subsystem response time to a read request by allowing the controller to satisfy the request from the cache memory rather than from the disk drives. A cache method used to decrease subsystem response times to a read request by allowing the controller to satisfy the request from the cache memory rather than from the disk drives. Reading data from cache memory is faster than reading data from a disk. The read cache is specified as either On or Off for each virtual disk. The default state is on. The process of regenerating the contents of a failed member data. The reconstruction process writes the data to a spare set disk and incorporates the spare set disk into the mirrorset, striped mirrorset or RAID set from which the failed member came. 1. Element Redundancy-The degree to which logical or physical elements are protected by having another element that can take over in case of failure. For example, each loop of a device-side loop pair normally works independently but can take over for the other in case of failure. 2. Data Redundancy-The level to which user data is protected. Redundancy is directly proportional to cost in terms of storage usage; the greater the level of data protection, the more storage space is required. A capability of the Enterprise storage system racks and enclosures to allow continuous system operation by preventing single points of power failure. • For a rack, two AC power sources and two power conditioning units distribute primary and redundant AC power to enclosure power supplies. • For a controller or drive enclosure, two power supplies ensure that the DC power is available even when there is a failure of one supply, one AC source, or one power conditioning unit. Implementing the redundant power configuration provides protection against the loss or corruption of data. An Enterprise Storage System controller pair and the associated disk drive enclosures. The Enterprise Storage System controller assigns a unique decimal reporting group number to each EMU on its loops. Each EMU collects disk drive environmental information from its own sub-enclosure and broadcasts the data over the enclosure address bus to all members of the reporting group. Information from enclosures in other reporting groups is ignored. See ambient temperature. S SCSI-3 SCSI-3 Enclosure Services selective presentation serial transmission SES snapclone The ANSI standard that defines the operation and function of Fibre Channel systems. See SES. The process whereby a controller presents a virtual disk only to the host computer which is authorized access. A method of transmission in which each bit of information is sent sequentially on a single channel rather than simultaneously as in parallel transmission. SCSI-3 Enclosures Services. Those services that establish the mechanical environment, electrical environment, and external indicators and controls for the proper operation and maintenance of devices within an enclosure. A virtual disk that can be manipulated while the data is being copied. Only an Active member of a virtual disk family can be snapcloned. The Snapclone, like a snapshot, reflects the contents of the source virtual disk at a particular point in time. Unlike the snapshot, the Snapclone is an actual clone of the source virtual disk and immediately becomes an independent Active member of its own virtual disk family. snapshot A temporary virtual disk (Vdisk) that reflects the contents of another virtual disk at a particular point in time. A snapshot operation is only done on an active virtual disk. Up to seven snapshots of an active virtual disk can exist at any point. The active disk and its snapshot constitute a virtual family. See also active virtual disk, and virtual disk family. 177

  • 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

read ahead
caching
A cache management method used to decrease the subsystem response time to a read request
by allowing the controller to satisfy the request from the cache memory rather than from the disk
drives.
read caching
A cache method used to decrease subsystem response times to a read request by allowing the
controller to satisfy the request from the cache memory rather than from the disk drives. Reading
data from cache memory is faster than reading data from a disk. The read cache is specified as
either On or Off for each virtual disk. The default state is on.
reconstruction
The process of regenerating the contents of a failed member data. The reconstruction process
writes the data to a spare set disk and incorporates the spare set disk into the mirrorset, striped
mirrorset or RAID set from which the failed member came.
redundancy
Element Redundancy—The degree to which logical or physical elements are protected by
having another element that can take over in case of failure. For example, each loop of a
1.
device-side loop pair normally works independently but can take over for the other in case
of failure.
2.
Data Redundancy—The level to which user data is protected. Redundancy is directly
proportional to cost in terms of storage usage; the greater the level of data protection, the
more storage space is required.
redundant power
configuration
A capability of the Enterprise storage system racks and enclosures to allow continuous system
operation by preventing single points of power failure.
For a rack, two AC power sources and two power conditioning units distribute primary and
redundant AC power to enclosure power supplies.
For a controller or drive enclosure, two power supplies ensure that the DC power is available
even when there is a failure of one supply, one AC source, or one power conditioning unit.
Implementing the redundant power configuration provides protection against the loss or
corruption of data.
reporting group
An Enterprise Storage System controller pair and the associated disk drive enclosures. The
Enterprise Storage System controller assigns a unique decimal reporting group number to each
EMU on its loops. Each EMU collects disk drive environmental information from its own
sub-enclosure and broadcasts the data over the enclosure address bus to all members of the
reporting group. Information from enclosures in other reporting groups is ignored.
room temperature
See
ambient temperature.
S
SCSI-3
The ANSI standard that defines the operation and function of Fibre Channel systems.
SCSI-3 Enclosure
Services
See
SES.
selective
presentation
The process whereby a controller presents a virtual disk only to the host computer which is
authorized access.
serial transmission
A method of transmission in which each bit of information is sent sequentially on a single channel
rather than simultaneously as in parallel transmission.
SES
SCSI-3 Enclosures Services. Those services that establish the mechanical environment, electrical
environment, and external indicators and controls for the proper operation and maintenance of
devices within an enclosure.
snapclone
A virtual disk that can be manipulated while the data is being copied. Only an Active member
of a virtual disk family can be snapcloned.
The Snapclone, like a snapshot, reflects the contents of the source virtual disk at a particular point
in time. Unlike the snapshot, the Snapclone is an actual clone of the source virtual disk and
immediately becomes an independent Active member of its own virtual disk family.
snapshot
A temporary virtual disk (Vdisk) that reflects the contents of another virtual disk at a particular
point in time. A snapshot operation is only done on an active virtual disk. Up to seven snapshots
of an active virtual disk can exist at any point. The active disk and its snapshot constitute a virtual
family.
See also
active virtual disk, and virtual disk family.
177