IBM ServeRAID-4 Ultra160 Series User Reference page 166

5. 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
operation, the drive being rebuilt is in the rebuild state, and the logical drive remains
critical until the rebuild operation has been successfully completed.
On IBM servers, when a hot-spare drive is available, the rebuild operation begins
automatically without the need to replace the failed drive. If more than one drive
fails within the same array, no rebuild takes place. If multiple drives fail in separate
arrays (one physical drive per array), the controller initiates a rebuild operation for
the logical drives within the array containing the first failed physical drive. This
rebuild operation is performed on the first hot-spare drive of sufficient size to
become a valid member of the array.
To start a hot-swap rebuild, do the following:
1. Without removing the drive completely, gently remove the physical drive from
2. Wait 20 seconds to allow the physical drive to completely stop spinning.
3. If you are certain there is nothing wrong with the physical drive you removed,
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IBM User's Reference: ServeRAID
the server, using the handle of the hot-swap tray. If necessary, refer to the
documentation that comes with your server on removing a physical drive.
Note: When power is removed from a hot-swap drive, the drive immediately
parks the heads, locks the actuator in the "landing zone", and begins
spinning down. However, the spinning down of the disk might require up
to 20 seconds after power is removed. Do not move the drive while it is
spinning down. Moving the drive while it is spinning down might damage
the drive.
gently reinstall the drive into the server.
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.
Make sure the drive is completely installed in the backplane connector.
Note: While it is possible to rebuild a defunct physical drive to an online
physical drive that is defective, avoid doing so.
Otherwise, replace the physical drive with a new drive that is the same size (or
larger) and continue with the rebuild operation.
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-4 Ultra160 SCSI Controller