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Chapter 1: Introduction to RAID
A RAID (Redundant Array of Independent Disks) is an array of multiple hard drives that are combined in a
way that provides faster performance and/or data safety. Your RTX unit is capable of creating and
managing several different varieties of RAID. You may choose your preferred RAID level based on
factors such as disk capacity, desired data safety, and desired performance.
Summary of RAID Levels
The RTX supports RAID Levels 0, 1, (0+1), 3, 5 and 6. RAID level 5 is most commonly used by those
seeking an optimal balance of speed and data safety.
RAID
Description
Level
0
Also known as striping. Data distributed
across multiple drives in the array. There is
no data protection.
1
Also known as mirroring. All data replicated
on separated disks. RAID 1 is almost always
2 disks.
This is a high availability solution, but due to
the 100% duplication, it is also a costly
solution.
0+1
Also known as Block-Interleaved Parity.
Data and parity information is subdivided
and distributed across all disks. Parity must
be equal to the smallest disk capacity in the
array. Parity information normally stored on
a dedicated parity disk.
3
Also known as Bit-Interleaved Parity. Data
and parity information is subdivided and
distributed across all disks. Parity must be
equal to the smallest disk capacity in the
array. Parity information normally stored on
a dedicated parity disk.
5
Also known as Block-Interleaved Distributed
Parity. Data and parity information is
subdivided and distributed across all disks.
Can withstand the failure of one drive, and
80& of drive capacity is usable.
6
Two different parity bits are used, to create
double redundancy. Can withstand the
failure of two drives, but only 60% of drive
capacity is usable.
R T X - U R U s e r ' s M a n u a l
RAID Features and Performance
Min.
Drives
1
2
3
3
3
4
Max.
Data Reliability
Drives
8
No data Protection
2
Lower than RAID 6;
Higher than RAID
3, 5
8
Lower than RAID 6;
Higher than RAID
3, 5
8
Lower than RAID 1,
10, 6;
Higher than a
single drive
8
Lower than RAID 1,
10, 6;
Higher than a
single drive
8
Higher than 1,10, 5
Data Transfer Rate
Very high
Reads are higher
than a single disk;
Writes are similar
to a single disk
Transfer rates are
more like RAID 1
than RAID 0
Reads are similar
to RAID 0; Writes
are slower than a
single disk
Reads are similar
to RAID 0; Writes
are slower than a
single disk
Slightly less than
RAID 5
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