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Hard Drive Installation and Replacement
D-2
Compaq Smart Array 5i Plus Controller and Battery Backed Write Cache User Guide
COMPAQ CONFIDENTIAL
Writer: Amy L. Laffitte File Name: m-appd Hard Drive Installation and Replacement
Codename: Executor Part Number: 266328-001 Last Saved On: 4/18/02 2:51 PM
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RAID 1+0 configurations can tolerate multiple drive failures as long as no failed
drives are mirrored to one another.
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RAID 5 configurations can tolerate one drive failure.
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RAID ADG configurations can tolerate simultaneous failure of two drives.
If more hard drives fail than the fault-tolerance method allows, fault tolerance is
compromised and the logical drive fails. In this case, all requests from the operating
system will be rejected with unrecoverable errors. The “Compromised Fault
Tolerance” section discusses possible ways to recover from this situation.
Recognizing Drive Failure
The LEDs on the front of each hard drive are visible through the front of the server or
external storage unit. When a drive is configured as a part of an array and attached to
a powered-on controller, the status of the drive can be determined from the
illumination pattern of these LEDs. Table D-1 describes the meaning of the various
LED combinations.
1
2
3
Figure D-1: Hard drive status LED indicators