RAID Level and Concatenation Performance Comparison

RAID Level and Concatenation Performance Comparison

RAID Level

Data Availability

Read Performance

Write Performance

Rebuild Performance

Minimum Disks Required

Suggested Uses

Concatenation

No gain

No gain

No gain

N/A

1 or 2 depending on the controller

More cost efficient than redundant RAID levels, use for noncritical data

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

Poor

N + 1(N = at least two disks)

Databases and other read-intensive transactional uses

RAID 6

Excellent

Sequential reads: good. Transactional reads: Very good

Fair, unless using write-back cache

Good

N + 2(N = at least two disks)

Databases and other read-intensive transactional uses, where data is redundancy is important.

RAID 10

Excellent

Very good

Fair

Good

2N x X

Data-intensive environments (large records)

RAID 50

Excellent

Very good

Fair

Fair

N + 2 (N = at least 4)

Medium-sized transactional or data-intensive uses

RAID 60

Excellent

Very good

Fair

Good

N + 4 (N = at least 4)

Medium-sized transactional or data-intensive uses, where data redundancy is important.

Reasons for RAID

Depending on how you implement RAID (which RAID level you use), the benefits include one or both of the following:

  • Faster performance; In RAID 0, 10, or 50 arrays, the host system can access multiple disks simultaneously. This improves performance because each disk in an array has to handle only part of the request. For example, in a two-disk array, each disk needs to provide only its part of the requested data.
  • Fault Tolerance; In RAID 1, 10, 5, 6, 50, and 60 arrays, the data is still accessible in the event of drive failure.
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