Dell PowerEdge R830 Integrated Remote Access Controller 8 Version 2.70.70.70 U - Page 186

Comparing RAID level performance

Page 186 highlights

RAID 10 characteristics: • Groups n disks as one large virtual disk with a capacity of (n/2) disks, where n is an even integer. • Mirror images of the data are striped across sets of physical disks. This level provides redundancy through mirroring. • When a disk fails, the virtual disk still works. The data is read from the surviving mirrored disk. • Improved read performance and write performance. • Redundancy for protection of data. Comparing RAID level performance 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. Table 37. RAID level performance comparison RAID Level RAID 0 Data Availability Read Performance None Very Good RAID 1 Excellent Very Good Write Performance Very Good Good Rebuild Performance N/A Good RAID 5 RAID 10 RAID 50 Good Excellent Good Sequential reads: Fair, unless using Fair good. writeback cache Transactional reads: Very good Very Good Fair Good Very Good Fair Fair Minimum Disks Suggested Required Uses N Noncritical data. 2N (N = 1) Small databases, database logs, and critical information. N + 1 (N = at least Databases and two disks) other read intensive transactional uses. 2N x X Data intensive environments (large records). N + 2 (N = at least 4) Medium sized transactional or 186 Managing storage devices

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RAID 10 characteristics:
Groups
n
disks as one large virtual disk with a capacity of (
n
/2) disks, where
n
is an even integer.
Mirror images of the data are striped across sets of physical disks. This level provides redundancy through mirroring.
When a disk fails, the virtual disk still works. The data is read from the surviving mirrored disk.
Improved read performance and write performance.
Redundancy for protection of data.
Comparing RAID level performance
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.
Table 37. RAID level performance comparison
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,
and critical
information.
RAID 5
Good
Sequential reads:
good.
Transactional
reads: Very good
Fair, unless using
writeback cache
Fair
N + 1 (N = at least
two disks)
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
186
Managing storage devices