User guide

2–2 Hardware architecture
Hitachi Unified Storage VM Block Module Hardware User Guide
System architecture overview
This section briefly describes the architecture of the Hitachi Unified Storage
VM storage system.
Hardware architecture
The basic system architecture is shown in the following diagram.
The system consists of two main hardware assemblies:
• A controller chassis that contains the logic and processing components
• One or more drive boxes that contains disk drives and/or solid state
(flash) drives. Drive boxes are not included in diskless systems.
These assemblies are explained briefly in Chapter 1.
HUS VM RAID implementation
This section provides an overview of the implementation of RAID technology
used on the Hitachi Unified Storage VM storage system.
The objectives of the RAID technology are the low cost, high reliability, and
high I/O performance of disk storage devices. To achieve these objectives,
this storage system supports levels 1, 5 and 6 of RAID technologies (in this
section, part of level 3 RAID technology is explained to make the outline of
RAID5 more understandable). The features of the levels of RAID
technologies are described below.
Figure 2-1: HUS VM Architecture Overview