Dell 341-7212 User Guide - Page 89

rebuilding data onto a new physical disk after a disk in a storage configuration, has failed.

Get Dell 341-7212 - PERC 6/i Integrated SAS RAID Controller Card Storage PDF manuals and user guides View all Dell 341-7212 manuals
Add to My Manuals
Save this manual to your list of manuals

Page 89 highlights

Read Policy A controller attribute indicating the current read policy mode. In Always read ahead mode, the controller reads sequentially ahead of requested data and stores the additional data in cache memory, anticipating that the data will be needed soon. This speeds up reads for sequential data, but there is little improvement when accessing random data. In No read ahead mode, read-ahead capability is disabled. In Adaptive read ahead mode, the controller begins using read-ahead if the two most recent disk accesses occurred in sequential sectors. If the read requests are random, the controller reverts to No read ahead mode. rebuild The regeneration of all data to a replacement disk in a redundant virtual disk 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. rebuild rate The percentage of central processing unit (CPU) resources devoted to rebuilding data onto a new physical disk after a disk in a storage configuration has failed. reclaim virtual disk A method of undoing the configuration of a new virtual disk. If you highlight the virtual disk in the Configuration Wizard and click the Reclaim button, the individual disk drives are removed from the virtual disk configuration. reconstruction rate The user-defined rate at which a reconstruct operation is carried out. redundancy A property of a storage configuration that prevents data from being lost when one physical disk fails in the configuration. redundant configuration A virtual disk that has redundant data on physical disks in the disk group that can be used to rebuild a failed physical disk. The redundant data can be parity data striped across multiple physical disks in a disk group, or it can be a complete mirrored copy of the data stored on a second physical disk. A redundant configuration protects the data in case a physical disk fails in the configuration. Glossary 89

  • 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
Glossary
89
Read Policy
A controller attribute indicating the current read policy mode. In
Always read
ahead
mode, the controller reads sequentially ahead of requested data and stores
the additional data in cache memory, anticipating that the data will be needed
soon. This speeds up reads for sequential data, but there is little improvement
when accessing random data. In
No read ahead
mode, read-ahead capability is
disabled. In
Adaptive read ahead
mode, the controller begins using read-ahead if
the two most recent disk accesses occurred in sequential sectors. If the read
requests are random, the controller reverts to
No read ahead
mode.
rebuild
The regeneration of all data to a replacement disk in a redundant virtual disk
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.
rebuild rate
The percentage of central processing unit (CPU) resources devoted to
rebuilding data onto a new physical disk after a disk in a storage configuration
has failed.
reclaim virtual disk
A method of undoing the configuration of a new virtual disk. If you highlight
the virtual disk in the Configuration Wizard and click the
Reclaim
button, the
individual disk drives are removed from the virtual disk configuration.
reconstruction rate
The user-defined rate at which a reconstruct operation is carried out.
redundancy
A property of a storage configuration that prevents data from being lost when
one physical disk fails in the configuration.
redundant configuration
A virtual disk that has redundant data on physical disks in the disk group that can
be used to rebuild a failed physical disk. The redundant data can be parity data
striped across multiple physical disks in a disk group, or it can be a complete
mirrored copy of the data stored on a second physical disk. A redundant
configuration protects the data in case a physical disk fails in the configuration.