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2.3.3
Consistency Check
2.3.4
Fault Tolerance
2.3.5
Disk Striping
2-4
·
A combination of any two of the above conditions
A consistency check verifies the correctness of redundant data in a RAID
array. For example, in a system with distributed parity, checking
consistency means computing the parity of the data drives and
comparing the results to the contents of the parity drives.
Fault tolerance is achieved through cooling fans, power supplies, and the
ability to hot swap drives. MegaRAID SCSI 320-1 provides hot swapping
through the hot spare feature. A hot spare drive is an unused online
available drive that MegaRAID SCSI 320-1 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.
Disk striping writes data across multiple disk drives instead of just one
disk drive, as shown in
Introduction to RAID
Copyright © 2002 by LSI Logic Corporation. All rights reserved.
Figure
2.1.
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