Table of Contents
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RAID Overview
Consistency Check
Fault Tolerance
8
ADAC Ultra2 S466 Hardware Guide
RAID (Redundant Array of Independent Disks) is a
collection of specifications that describe a system for
ensuring the reliability and stability of data stored on large
disk subsystems. A RAID system can be implemented in a
number of different versions (or RAID Levels). The
standard RAID levels are 0, 1, 3, and 5. ADAC Ultra2
S466 supports all standard RAID levels and RAID levels
10, 30, and 50, special RAID versions supported by ADAC
Ultra2 S466.
In RAID, check consistency verifies the correctness of
redundant data in an array. For example, in a system with
dedicated parity, checking consistency means computing
the parity of the data drives and comparing the results to
the contents of the dedicated parity drive.
Fault tolerance is achieved through cooling fans, power
supplies, and the ability to hot swap drives. ADAC Ultra2
S466 provides hot swapping through the hot spare feature.
A hot spare drive is an unused online available drive that
ADAC Ultra2 S466 instantly plugs into the system when
an active drive fails.
After the hot spare is automatically moved into the RAID
subsystem, the failed drive is automatically rebuilt. The
RAID disk array continues to handle request while the
rebuild occurs.
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