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APPENDIX
Summary of RAID Levels
ARC-8050 Thunderbolt RAID storage supports RAID Level 0, 1,
10(1E), 3, 5, 6, 30, 50 and 60. The following table provides a
summary of RAID levels.
RAID Level Comparision
RAID
Level
Description
Disks
Requirement
(Minimum)
Data
Availability
0
Also known as striping.
Data distributed across multiple
drives in the array. There is no data
protection.
1
No data
Protection
1
Also known as mirroring.
All data replicated on 2 separated
disks. N is almost always 2. Due to
this is a 100 % duplication, so is a
high costly solution.
2
Up to one disk
failure
10(1E)
Also known as mirroring and striping.
Data is written to two disks
simultaneously, and allows an odd
number or disk. Read request can be
satisfied by data read from wither
one disk or both disks.
3
Up to one disk
failure in each
sub-volume
3
Also known Bit-Interleaved Parity.
Data and parity information is
subdivided and distributed across
all data disks. Parity information
normally stored on a dedicated parity
disk.
3
Up to one disk
failure
5
Also known Block-Interleaved
Distributed Parity.
Data and parity information is
subdivided and distributed across all
disk. Parity information normally is
interspersed with user data.
3
Up to one disk
failure
6
RAID 6 provides highest reliability,
but not widely used. Similar to
RAID 5, but does two different
parity computations or the same
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.
4
Up to two disk
failure
