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Chapter 1 Introduction
RAID LEVELS
RAID Level 0 : " Disk Striping " High I/O Performance
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Improved I/O performance is the major reason for using RAID level 0. No protection is
provided against data loss due to member disk failures. A RAID level 0 array by itself is
thus an unsuitable storage medium for data that can not easily be reproduced, or for data
that must be available for critical system operation. It is more suitable for data that can be
reproduced or is replicated on other media.
A RAID level 0 array can be particularly useful for
A RAID level 0 array can be particularly useful for :
A RAID level 0 array can be particularly useful for :
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Storing program image libraries or runtime libraries for rapid
normally read only.
•
Storing large tables or other structures of read only data for rapid application access.
Like program images, the data should be backed up on highly reliable media, from which
it can be recreated in the event of a failure.
•
Collecting data from external sources at very high data transfer rates.
RAID level 0 arrays are not particularly suitable for :
•
Applications which make sequential requests for small amount of data. These
applications will spend most of their I/O time waiting for disks to spin, whether or not they
use striped arrays as storage media.
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Applications which make synchronous random requests for small amounts of data.
Figure: Disk Striping
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Array Management Software
Provides Logical to Physical Mapping
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Disk 1
Disk 2
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4
3
2
1
Disk Array Controller
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4
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Disk 3
Disk 4
loading, these libraries are
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Data
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Physical
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