50
MIRRORING
Mirroring (RAID 1) consists of at least two drives storing duplicate copies of the
same data. In this mode, the data is simultaneously written to two disks. Thus,
the storage capacity of a two-disk array is combined into a single disk and the
capacity is limited to the size of the smallest disk. In Mirroring mode, identical
HDDs of the same capacity and RPM from the same manufacturer are highly
recommended for best capacity utilization.
Mirroring offers the highest level of data protection. Mirroring is typically used in
mission-critical systems, such as payroll, accounting, and ERP databases.
Logical Drive
Physical Drive
READ
WRITE
A
B
C
D
Data
A
B
C
D
Host
RAID
CONTROLLER
9GB
9GB
=
+
9GB
Read/ Write
Hard Disk
RAID
A
B
C
D
A
B
C
D
In Mirroring mode, if one disk in the array fails, the data in the backup disk is
still available.
