User's Manual

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Related Information:
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See the following:
l "Organizing Data Storage for Availability and Performance"
l "Comparing RAID Level Performance"
l "Controller-supported RAID Levels"
l "Number of Physical Disks per Virtual Disk"
l "Maximum Number of Virtual Disks per Controller"
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Comparing RAID Level Performance
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The following table compares the performance characteristics associated with the more common RAID levels. This table provides general guidelines for
choosing a RAID level. Evaluate your specific environment requirements before choosing a RAID level.
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Table 5-1.RAIDLevelPerformanceComparison
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NOTE: The following table does not show all RAID levels supported by Storage Management. For information on all RAID levels supported by Storage
Management, see "Choosing RAID Levels."
RAID
Level
Data
Availability
Read Performance
Write Performance
Rebuild
Performance
Minimum Disks
Required
Suggested Uses
RAID
0
None
Very Good
Very Good
N/A
N
Noncritical data
RAID
1
Excellent
Very Good
Good
Good
2N
(N = 1)
Small databases, database logs, critical
information
RAID
5
Good
Sequential reads: good.
Transactional reads: Very good
Fair, unless using
write-back cache
Fair
N + 1
(N = at least
two disks)
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Databases and other read-intensive
transactional uses
RAID
10
Excellent
Very Good
Fair
Good
2N x X
Data-intensive environments (large
records)
RAID
50
Good
Very Good
Fair
Fair
N + 2
(N = at least 4)
Medium-sized transactional or data-
intensive uses
RAID
6
Excellent
Sequential reads: good.
Transactional reads: Very good
Fair, unless using
write-back cache
Poor
N + 2
(N = at least
two disks)
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Critical information. Databases and
other read-intensive transactional uses.
RAID
60
Excellent
Very Good
Fair
Poor
X x (N + 2)
(N = at least 2)
Critical information. Medium-sized
transactional or data-intensive uses.
N = Number of physical disks
X = Number of RAID sets