HP StorageWorks MSA1510i HP Storage Management Utility user guide (383075-002, - Page 90

Choosing a RAID level, Table 7 Summary of RAID methods

Get HP StorageWorks MSA1510i PDF manuals and user guides View all HP StorageWorks MSA1510i manuals
Add to My Manuals
Save this manual to your list of manuals

Page 90 highlights

Table 7 Summary of RAID methods RAID 0 RAID 1+0 RAID 5 Alternative name Striping Mirroring Distributed Data Guarding (DDG) Usable drive space* 100% 50% 67% to 93% Usable drive space formula n n/2 (n-1)/n Minimum number of physical drives 1 2 3 Tolerates physical drive failure? No Yes Yes Tolerates simultaneous failure of more than one No physical drive? Only if no two failed drives are in No a mirrored pair Read performance High High High Write performance High Medium Low Relative cost Low High Medium *Values for usable drive space are calculated with these assumptions: • All physical drives in the array have the same capacity. • Online spares are not used. • No more than 14 physical drives are used per array for RAID 5. • No more than 56 drives are used with RAID 6. RAID 6 Advanced Data Guarding (ADG) 50% to 96% (n-2)/n 4 Yes Yes High Low Medium Choosing a RAID level Use Table 8 to help you determine the best RAID level for your environment. Table 8 Choosing a RAID level Most important characteristic Also important Suggested RAID level Fault tolerance Cost effectiveness Cost effectiveness I/O performance Fault tolerance RAID 6 RAID 1+0 RAID 6* I/O performance RAID 5 (RAID 0 if fault tolerance is not required) I/O performance Cost effectiveness Fault tolerance RAID 5 (RAID 0 if fault tolerance is not required) RAID 1+0 90 Storage overview

  • 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
Table 7 Summary of RAID methods
RAID 0
RAID 1+0
RAID 5
RAID 6
Alternative name
Striping
Mirroring
Distributed Data
Guarding (DDG)
Advanced Data
Guarding (ADG)
Usable drive
space*
100%
50%
67% to 93%
50% to 96%
Usable drive space
formula
n
n/2
(n-1)/n
(n-2)/n
Minimum number
of physical drives
1
2
3
4
Tolerates physical
drive failure?
No
Yes
Yes
Yes
Tolerates
simultaneous failure
of more than one
physical drive?
No
Only if no two
failed drives are in
a mirrored pair
No
Yes
Read performance
High
High
High
High
Write performance
High
Medium
Low
Low
Relative cost
Low
High
Medium
Medium
*Values for usable drive space are calculated with these assumptions:
•
All physical drives in the array have the same capacity.
•
Online spares are not used.
•
No more than 14 physical drives are used per array for RAID 5.
•
No more than 56 drives are used with RAID 6.
Choosing a RAID level
Use
Table 8
to help you determine the best RAID level for your environment.
Table 8 Choosing a RAID level
Most important characteristic
Also important
Suggested RAID level
Fault tolerance
Cost effectiveness
RAID 6
I/O performance
RAID 1+0
Cost effectiveness
Fault tolerance
RAID 6*
I/O performance
RAID 5 (RAID 0 if fault tolerance
is not required)
I/O performance
Cost effectiveness
RAID 5 (RAID 0 if fault tolerance
is not required)
Fault tolerance
RAID 1+0
90
Storage overview