Table of Contents
Advertisement
FIBRE-to-SAS/SATA RAID SUBSYSTEM
Chapter 4 RAID Levels
RAID stands for Redundant Array of Independent Disks. A RAID system consists of
two or more disks in parallel. This array of disks appears as one disk drive to the
host computer offering enhanced performance or data reliability or both.
There are different RAID Levels with each level being suited to a particular
application. For example, RAID Level 1 uses mirroring to hold your data in 2
separate but identical locations. If a disk fails the RAID controller will use either the
data disk(s) or the mirror disk(s) for data recovery giving you constant access to
your data. This RAID Level is particularly suited to mission critical applications such
as accounting systems.
The following is a brief list of the supported RAID levels.
RAID 0 - Striping without Fault Tolerance
In a RAID 0 system the data is broken
down in to equal blocks and each block
is then written to a different disk in the
RAID. The performance is excellent as
the I/O load is shared equally between
the all disks in the RAID. The following
illustration shows a typical RAID 0.
Advantages
Good performance both in read
and write operations as there is
no overhead expended on
parity controls.
All storage capacity can be
used; there is no disk
overhead.
Easy to implement.
54
User Manual
Disadvantages
Not fault-tolerant. If
one disk fails, all data
in the RAID 0 array are
lost.
Reliability is much less
than a single disk - any
media errors can cause
data loss.
Ideal Use
Not
recommende
d for any
mission-
critical
systems or
applications
Advertisement
Table of Contents
