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Appendices
User Guide Page 5-1
5. RAID Overview
5.1 How RAID Works
RAID, or Redundant Array of Independent Disks, is a data-storage technology that spreads data
across multiple drives. This technology provides several benefits:
:

Data redundancy for protection and availability.

Higher performance as a result of reading or writing on several drives simultaneously.

Scalability for expansion of storage.
Accusys RAID systems use a hardware controller to manage multiple drives as one or more
RAID array group, which offloads RAID task from host, and provides independent, fast and
highly efficient storage.
The way of controller stores and retrieves data on the RAID system is determined by the RAID
level and storage method you choose. Once you have defined a group of drives as an array
group, each logical disk appears to the host system as one Logical Unit (LUN), regardless of the
number of actual drives in that logical unit.
RAID System Host System
5.2 RAID Levels
The RAID system supports several RAID levels and configurations. Each level has a different
architecture and provides varying degrees of performance and fault tolerance.
5.2.1 RAID 0: Striping
RAID level 0, striping only, is the fastest and most efficient array type, but offer no fault-
tolerance. Any drive failure will destroy the data in the array.
Hard Drive
100GB Hard Drive
100GB Hard Drive
100GB
Array Group
LUN (Logical Unit)
300GB
Logical Disk