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RAID Level
Description
Also known as striping. Data distributed across multiple drives in the
0
array. There is no data protection.
Also known as mirroring. All data replicated on 2 separated disks. N is
1
almost always 2. Due to this is a 100 % duplication, so is a high costly
solution.
Also known as mirroring and striping. Data is written to two disks
10(1E)
simultaneously, and allows an odd number or disk. Read request can
be satisfied by data read from wither one disk or both disks.
Also known Bit-Interleaved Parity. Data and parity information is
3
subdivided and distributed across all data disks. Parity information
normally stored on a dedicated parity disk.
Also known Block-Interleaved Distributed Parity. Data and parity
5
information is subdivided and distributed across all disk. Parity
information normally is interspersed with user data.
RAID 6 provides highest reliability, but not widely used. Similar to
RAID 5, but does two different parity computations or the same
6
computation on overlapping subsets of the data. The RAID 6 can offer
fault tolerance greater that RAID 1 or RAID 5 but only consumes the
capacity of 2 disk drives for distributed parity data.
RAID 30 is a combination multiple RAID 3 volume sets with RAID 0
30
(striping)
RAID 50 is a combination multiple RAID 5 volume sets with RAID 0
50
(striping)
RAID 60 is a combination multiple RAID 6 volume sets with RAID 0
60
(striping)
RAID Level Comparsion
125
Disks
Data
Requirement
Availability
(Minimum)
No data
1
Protection
Up to one
2
disk failure
Up to one
disk failure
3
in each
sub-volume
Up to one
3
disk failure
Up to one
3
disk failure
Up to two
4
disk failure
Up to one
disk failure
6
in each
sub-volume
Up to one
disk failure
6
in each
sub-volume
Up to two
8
disk failure
in each
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