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Appendix B: RAID Basics
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Overview
A Redundant Array of Independent Disks (RAID) is an array of several hard disks that provide data
security and high performance. A RAID system accesses several hard disks simultaneously, which
improves I/O performance over a single hard disk. Data security is enhanced by a RAID, since data
loss due to a hard disk failure is minimized by regenerating redundant data from the other RAID hard
disks.
•
Benefits
RAID improves I/O performance, and increases data security through fault tolerance and redundant
data storage.
Improved Performance
RAID provides access to several hard disk drives simultaneously, which greatly increases I/O
performance.
Data Security
Hard disk drive failure unfortunately is a common occurrence. A RAID helps prevent against the loss
of data due to hard disk failure. A RAID offers additional hard disk drives that can avert data loss from
a hard disk drive failure. If a hard drive fails, the RAID volume can regenerate data from the data and
parity stored on its other hard disk drives.
RAID Levels
The Thecus IP storage supports standard RAID levels 0, 1, 5, 6, 10, 50, 60 and JBOD. You choose a RAID
level when you create a system volume. The factors for selecting a RAID level are:
•
Your requirements for performance
•
Your need for data security
•
Number of hard disk drives in the system, capacity of hard disk drives in the system
The following is a description of each RAID level:
RAID 0
RAID 0 is best suited for applications that need high bandwidth but do not require a high level of
data security. The RAID 0 level provides the best performance of all the RAID levels, but it does not
provide data redundancy.
RAID 0 uses disk striping and breaking up data into blocks to write across all hard drives in the vol�
ume. The system can then use multiple hard drives for faster read and write. The stripe size parame�
ter that was set when the RAID was created determines the size of each block. No parity calculations
complicate the write operation.
RAID 1
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Appendix B: RAID Basics
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