Vsp G1000, Vsp G1500, And Vsp F1500 Raid Implementation; Array Groups And Raid Levels; Raid 1 - Hitachi G1500 Hardware Manual

VSP G1000, VSP G1500, and VSP F1500 RAID implementation

The benefits of RAID technology are low cost, high reliability, and high I/O performance
of data storage devices. To gain these benefits, this storage 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 figure 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
configured in four-drive RAID 5 parity groups (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 figures illustrate the RAID 1 configurations. The tables following the
figures describe each configuration.
Hitachi Virtual Storage Platform G1000, G1500, and VSP F1500 Hardware Guide
VSP G1000, VSP G1500, and VSP F1500 RAID implementation
Chapter 3: Hardware architecture
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