Raid 1 - LaCie 2big Network User Manual

LaCie 2big Network
User Manual

5.3. RAID 1

RAID 1 is a secure RAID mode that requires at least 2 drives and
works with pairs of drives (Fig.
the computer and the combined available capacity of both drives
is limited to the capacity of the lowest-capacity disk. If one physical
disk fails, the data is available immediately on the second disk. No
data is lost if one disk fails.
Applications
RAID 1 provides maximum data safety in the event of a single disk
failure, but because data is written twice, performance is reduced
slightly when writing. RAID 1 is a good choice when safety is more
important than speed.
How RAID 1 Capacity Is Calculated
Each disk in a RAID 1 system should have the same capacity.
Storage capacity in a RAID level 1 configuration is calculated by
multiplying the number of drives by the disk capacity and dividing
by 2, or
C = n*d/2
where:
C = available capacity
n = number of disks
d = disk capacity
For example, in a RAID 1 array with four drives each with a capac-
ity of 1000GB, the total capacity of the array would be 2000GB:
C = (4*1000)/2
85). One logical volume mounts on
RAID 1
A1
B1
C1
D1
E1
Fig. 85
RAID and Disks
page 53
A1
B1
C1
D1
E1