Hitachi G1500 - VSP G1000, VSP G1500, and VSP F1500 RAID Implementation; Array Groups and RAID Levels

VSP G1000, VSP G1500, and VSP F1500 RAID implementation
The benets of RAID technology are low cost, high reliability, and high I/O performance
of data stor
age de
vices. T
o gain these benets, this stor
age system supports RAID levels
1, 5 and 6.
Array groups and RAID levels
An array group (also called parity group) is the basic unit of storage capacity for the
storage system. In RAID 1, an array group is a set of four physical drives where one drive
is installed in the same location in each of four contiguous disk trays in the same drive
chassis. The following gure shows part of an SFF drive chassis where two RAID 1 array
groups are set up. RAID 1 is shown by yellow rectangles. The RAID 2 is shown by the red
rectangles.
Figure 9 RAID group example
The storage system supports the following RAID levels: RAID 1, RAID 5, and RAID 6. When
congured in four-drive RAID 5 parity gr
oups (3D+1P), 75% of the raw capacity is
available to store user data, and 25% of the raw capacity is used for parity data.
RAID 1
The following two gures illustrate the RAID 1 congurations. The tables following the
gures describe each conguration.
VSP G1000, VSP G1500, and VSP F1500 RAID implementation
Chapter 3: Hardware architecture
Hitachi Virtual Storage Platform G1000, G1500, and VSP F1500 Hardware Guide 61