IBM Netfinity ServeRAID-4L Ultra160, User Reference

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Rebuilding a defunct drive
A physical drive is marked defunct when there is a loss of communication between
the controller and the physical drive. This can be caused by any of the following:
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An improperly connected cable, physical drive, or controller
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Loss of power to a drive
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An improperly assembled SCSI channel in an unsupported configuration
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A defective cable, backplane, physical drive, or controller
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Connecting unsupported SCSI devices (such as tape drives or CD-ROM drives)
to the same SCSI channel used for an array.
In each case, after the communication problem is resolved, a rebuild operation is
required to reconstruct the data for the device in its disk array. The ServeRAID
controllers can reconstruct RAID level-1 and RAID level-5 logical drives, but they
cannot reconstruct data stored in RAID level-0 logical drives because, RAID level-0
is not redundant. If an array contains only RAID level-0 logical drives, the logical
drives in the array are marked offline and the logical drives might contain damaged
data. You cannot rebuild the logical drives. You must replace the physical drives
and restore your data.
To prevent data-integrity problems, the ServeRAID controllers set the RAID level-0
logical drives in the affected array to blocked during the rebuild operation for RAID
level-1 or RAID level-5. After the rebuild operation completes, you can unblock the
RAID level-0 logical drives, and access them once again. Remember, however, that
the RAID level-0 logical drives might contain damaged data.
Steps for recovering from defunct drives
If the defunct drives are not part of an array, contact your IBM service
representative.
If the defunct drives are part of an array, do the following:
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If more than one physical drive in an array is defunct, contact your IBM service
representative.
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If a rebuild operation is in progress, wait until the rebuild is complete.
v
If a rebuild is not in progress and only one physical drive in the array is defunct,
do the following:
1. Verify the cables, physical drives, and controllers are installed properly.
2. Attempt to rebuild the defunct physical drive by performing a Hot-Swap
Rebuild. Refer to “Rebuilding a hot-swap drive” for instructions.
Note: If multiple drives fail in separate arrays (one physical drive per array),
then replace each defunct physical drives. If multiple physical drives
fail at the same time within the same array, contact your IBM service
representative.
3. If the Hot-Swap Rebuild fails, contact your IBM service representative.
Rebuilding a hot-swap drive
A Hot-Swap Rebuild refers to a Rebuild operation that is started by the ServeRAID
controller when it detects that a drive that is part of an array and in the defunct
state has been removed and reinserted on the SCSI cable or backplane. The
reinsertion of the physical drive, whether it is the same drive or a new drive, will
trigger the ServeRAID controller to start the rebuild operation. During the rebuild
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-4L Ultra160 SCSI Controller User’s Reference