LaCie 4big Quadra Enterprise Class
• D
esign
by
n
eil
P
oulton
RAID
User Manual
page 15
3.1.2. RAID 10
RAID 10 (also called RAID 1+0) is another RAID level that combines
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
Fig. 08
.
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 second 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 (
Fig. 09
). Concatenation provides no per-
formance 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 capacities
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
Fig. 08
Fig. 09
Applications
RAID 10 provides good speeds because of RAID 0 striping,
but cuts the available capacity of a device in half (assume all
disks in the array have the same capacity).
