Raid 5 - Sabio DM4 User Manual

RAID 5

RAID 5 uses block-level striping with parity data distributed across all member
disks. It is also called Parity RAID. Every time a block is written to a disk in a
RAID 5 disk array, a parity block is generated within the same stripe. A block is
composed of many consecutive sectors on a disk. A series of blocks (a block
from each of the disks in an array) is collectively called a "stripe". The parity
information inside the parity block is not the identical copy of the source data. It
is generated via parity calculation. RAID 5 mode provides decent data protection
and fault tolerance. The speed of operation is average in comparison to other
RAID modes.
The number of disks supported by RAID 5 is 3 or 4. The storage capacity
will become all disks in total but minus 1. The capacity is limited to the size of
the smallest disks.
A1
B1
C1
Dp
Disk 1
If one of the disks fails, the data can be reconstructed through parity
calculation once the broken disk is replaced with a new one.
RAID 5
A2
B2
Cp
D1
Disk 2
22
A3
Bp
C2
D2
Disk 3 Disk 4
Ap
B3
C3
D3