Recovering from a Disk Drive Failure
This section describes how to recover when a disk drive or SSD fails:
• If the logical drive is protected by a hot spare, see
Failed Disk Drive Protected by a Hot Spare
on page
109.
• If the logical drive is not protected by a hot spare, see
Failed Disk Drive Not Protected by a Hot Spare
on page 109.
• If there is a disk drive failure in more than one logical drive simultaneously, see
Failure in Multiple
Logical Drives Simultaneously
on page 109.
• If it is a RAID 0 logical drive, see
Disk Drive Failure in a RAID 0 Logical Drive
on page 110.
• If multiple disk drives fail within the same logical drive, see
Multiple Disk Drive Failures in the Same
Logical Drive
on page 110.
Failed Disk Drive Protected by a Hot Spare
If a disk drive in a logical drive fails and that logical drive is protected by a hot spare, the hot spare is
automatically incorporated into the logical drive and takes over for the failed drive.
For example, if a disk drive fails in a RAID 5 logical drive, the logical drive is automatically rebuilt, with
its data reconstructed using the hot spare in place of the failed drive. You can access the logical drive
while it's rebuilding.
To recover from the failure:
1. Remove and replace the failed disk drive, following the manufacturer's instructions.
2. If copyback is not enabled—Remove the ‘hot spare’ designation from the original hot spare (the disk
drive that was built into the logical drive). See
Removing or Deleting a Dedicated Hot Spare
on page
47 for instructions. Then, designate a new hot spare to protect the logical drives on that controller.
If copyback is enabled—Data is automatically moved back to its original location once the controller
detects that the failed drive has been replaced. No action is required. See
Enabling Copyback
on
page 48 for more information.
Failed Disk Drive Not Protected by a Hot Spare
If a disk drive in a logical drive fails when the logical drive is not protected by a hot spare, remove and
replace the failed disk drive. The controller detects the new disk drive and begins to rebuild it. You can
access the logical drive while it's rebuilding.
For example, when one of the disk drives fails in a RAID 1 logical drive, the logical drive is not automatically
rebuilt. The failed disk drive must be removed and replaced before the logical drive can be rebuilt.
If the controller fails to rebuild the logical drive, check that the cables, disk drives, and controllers are
properly installed and connected. Then, if necessary, follow the instructions in
Rebuilding Logical Drives
on page 111.
Failure in Multiple Logical Drives Simultaneously
If a disk drive fails in more than one logical drive at the same time (one failure per logical drive), and
the logical drives have hot spares protecting them, the controller rebuilds the logical drives with these
limitations:
• A hot spare must be of equal or greater size than the failed disk drive it's replacing.
• Failed disk drives are replaced with hot spares in the order in which they failed. (The logical drive
that includes the disk drive that failed first is rebuilt first, assuming an appropriate hot spare is
available—see the previous bullet.)
Note: If the number of disk drive failures exceeds the number of hot spares, see
Failed
Disk Drive Not Protected by a Hot Spare
on page 109.
If copyback is enabled, data is moved back to its original location once the controller detects that the
failed drive has been replaced. See
Enabling Copyback
on page 48 for more information.
109
Proprietary and Confidential to PMC-Sierra, Inc.
Document No.: CDP-00278-01-A Rev. A, Issue:
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