LaCie 4big Quadra
• D
esign
by
N
eil
P
oulton
RAID
User Manual
page 16
3.1.2. RAID 10
RAID 10 (also called RAID 1+0) is another RAID level that com-
bines the attributes of other levels, specifically RAID 1 and RAID
0. It is a “mirror of stripes”, meaning that data is striped across
two mirrored arrays. The Striping occurs between arrays and the
mirroring occurs within the same array. See the diagram, right.
In a RAID 10 array, one disk from each mirrored pair can fail
with no data loss. However, the working disk in an array with a
failed disk becomes a weak point for the entire array. If the sec-
ond disk in a mirrored pair fails, the entire array is lost.
3.1.3. Concatenation
When disks are concatenated, their capacities are combined
and data is written to the primary disk in the array until is it full,
and then to successive disks. Concatenation provides no perfor-
mance advantage or added measure of data safety. It is simply
a method of combining more than one physical disk into one
volume for greater overall capacity.
Concatenation allows full use of the capacity of all disks in the
array and most data can survive a disk failure. Only data on the
failed disk and data that is partially written on the failed disk and
an operative disk is lost.
Offers the maximum possible capacity by combining the capaci-
ties of several drives into one large volume.
RAID 1
RAID 1
RAID 0
A2
A4
A6
A8
RAID 10
A2
A6
A8
A4
A1
A3
A7
A5
A1
A3
A5
A7
Disk 1
Disk 2
Disk 3
Disk 4
Concatenation
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Disk 1
Disk 2
Disk 3
Disk 4
Applications
RAID 10 provides good speeds because of RAID 0 strip-
ing, but cuts the available capacity of a device in half
(assume all disks in the array have the same capacity).
