Board Components and Features
Compaq Smart Array 5300 Controller User Guide
1-9
COMPAQ CONFIDENTIAL
Writer: John Turner File Name: b-ch1 board components.doc
Codename: SilverHammer Part Number: 135606-004 Last Saved On: 7/22/02 11:09 AM
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Auto-Reliability Monitoring
(ARM) is a background process that scans hard
drives for bad sectors in fault-tolerant logical drives. ARM also verifies the
consistency of parity data in logical drives that are using RAID 5 or RAID ADG.
This process assures that you can recover all data successfully if a drive failure
occurs in the future. ARM operates only when you select a fault-tolerant
configuration (RAID 1 or higher).
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Dynamic sector repair
by the controller automatically remaps any sectors that
have media faults (detected either during normal operation or by auto reliability
monitoring).
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S.M.A.R.T.
is an industry-standard diagnostic and failure-prediction feature of
hard drives, developed by Compaq in collaboration with the hard drive industry.
It monitors several factors that can be used to predict imminent hard drive failure
due to mechanical causes. Such factors include the condition of the read/write
head, the seek error rate, and the spin-up time. When a threshold value is
exceeded for one of these factors, the drive sends an alert that failure is
imminent. Thus, the user can back up data and replace the drive before drive
failure occurs.
NOTE:
An online spare does not become active and start rebuilding when the imminent
failure alert is sent, because the degraded drive has not actually failed yet and is still
online. The online spare is activated only after a drive in the array has failed.
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Drive failure alert features
cause an alert message to be displayed on the
system monitor when drive failure occurs. Different Compaq server models use
different messages for different situations. These messages are described in your
server documentation.
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Interim data recovery
occurs if a drive fails in fault-tolerant configurations
(RAID 1 or higher). In this situation, the system will still process I/O requests,
but at a reduced performance level. Replace the failed drive as soon as possible
to restore performance and full fault tolerance for that logical drive. Otherwise, if
another hard drive fails before data has been rebuilt, the logical volume will fail
and data will be lost. Refer to Appendix E for more information about recovering
from drive failure.
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POST
or the
Array Diagnostics Utility
will also reveal imminent drive failure.
