Areca 24/4 Internal/External Port Pcie 3.0 12 Gb/s SAS/SATA Raid Controller 2Gb Cache - Manual (Page 263)

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APPENDIX
Summary of RAID Levels
12Gb/s SAS RAID controller supports RAID Level 0, 1, 10(1E), 3, 5, 6,
30, 50, 60 and Pass-Through Disk. The following table provides a sum-
mary of RAID levels.
RAID Level Comparsion
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 simple 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
1 Also known as Multi Mirroring.
All data replicated on 3 separated disks.
N is almost always 3. Due to this is a
100 % duplication, so is a high costly
solution.
3 Up to two disks
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