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3 – Drive Mode Descriptions
The following two pages describe the various drive modes
supported by the R400 RAID USB 3.0. To configure the
Fusion R400 RAID USB 3.0's drives, refer to Select Drive
Mode on page 5.
Support Note:
In all modes except JBOD, Sonnet
strongly recommends you use four identical drives
in the Fusion R400 RAID USB 3.0. Due to varying operating
characteristics, the use of different drives may lead to issues
ranging from reduced total capacity, to louder operation, to
RAID failures.
RAID 0: Striping, No Redundancy
RAID 0 (striping) is based on the concept that increased
performance can be achieved by simultaneously accessing
data across multiple drives, increasing data transfer rates while
reducing average access time by overlapping drive seeks.
Drives are accessed alternately, as if stacked one on top of the
other. Although RAID 0 is typically used by applications
requiring high performance for non-critical data, when
used in the R400 RAID USB 3.0 it's only advantage next to
RAID 5 is increased formatted capacity. RAID 0 provides
no data protection; If one drive fails, all data within that
stripe set is lost. See Figure 5.
When configured as a RAID 0 volume, the volume size is
equal to the full capacity of the drives.
WARNING:
RAID 5 and 10 configuration improves
data accessibility and reliability during normal
operations. However, you still need a good backup strategy
for long-term protection of your data.
RAID 10: Striping, Mirror Spans Two Drives
RAID 10 increases data transfer rates while ensuring security
by writing the exact same data simultaneously to two or
more different drives. Any one of the four drives can fail, and
the volume will continue to function. RAID 10 is used in
applications requiring higher performance and redundancy,
combining the attributes of RAID Levels 1 and 0. See
Figure 6.
RAID 10 offer 50% of the total capacity of the four drives.
Span: Concatenation, Volume Spans Four Drives
Span mode creates a single, large volume that spans all four
drives, writing files to the capacity of the first drive, then the
second drive, and so on. See Figure 7. Span mode provides
no data protection.
When configured as a spanned volume, the total volume
size depends on the drive with the smallest capacity.
RAID 0: Striping, No Redundancy
Disk 1
Stripe 1
Stripe 2
Stripe 3
Striping, Mirror Spans Two Drives
Disk 1
Stripe 1
Data 1
Stripe 2
Data 3
Stripe 3
Data 5
Span (Concatenation, Big)
Disk 1
Disk 2
Data 1
Data 25
Data 2
Data 26
Data 3
Data 27
Data 4
Data 28
Data 5
Data 29
Data 6
Data 30
3
Disk 2
Disk 3
Figure 5
RAID 10:
Disk 2
Disk 3
Data 1
Data 1
Data 2
Data 3
Data 3
Data 4
Data 5
Data 5
Data 6
Figure 6
Disk 3
Disk 4
Data 49
Data 73
Data 50
Data 74
Data 51
Data 75
Data 52
Data 76
Data 53
Data 77
Data 54
Data 78
Figure 7
Disk 4
Disk 4
Data 2
Data 2
Data 4
Data 4
Data 6
Data 6
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