HP StoreAll Storage - Manual (Page 26)

• Open HP SIM or similar management software utility and inspect each physical drive in the array
to confirm that no other drives have errors.
• Be sure that the array has a current, valid backup.
• Use replacement drives that have a capacity at least as great as that of the smallest drive in the
array. The controller immediately fails drives that have insufficient capacity.
To minimize the likelihood of fatal system errors, take these precautions when removing failed drives:
• Do not remove a degraded drive if any other drive in the array is offline (the online LED is off). In
this situation, no other drive in the array can be removed without data loss.
• Do not remove a second drive from an array until the first failed or missing drive has been replaced
and the rebuild process is complete. (The rebuild is complete when the Online LED on the front of
the drive stops blinking.)
Automatic data recovery (rebuild)
When you replace a hard drive in an array, the controller uses fault-tolerance information on the
remaining drives in the array to reconstruct the missing data (the data that was originally on the
replaced drive) and write it to the replacement drive. This process is called automatic data recovery,
or rebuild. If fault tolerance is compromised, this data cannot be reconstructed and is likely to be
permanently lost.
Time required for a rebuild
• The time required for a rebuild varies considerably, depending on several factors:
• The priority that the rebuild is given over normal I/O operations
• The amount of I/O activity during the rebuild operation
• The rotational speed of the hard drives
• The availability of drive cache
• The brand, model, and age of the drives
• The amount of unused capacity on the drives
• The number of drives in the array
Allow approximately 5 minutes per gigabyte without any I/O activity during the rebuild process. This
figure is conservative, and newer drive models usually require less time to rebuild.
System performance is affected during the rebuild, and the system is unprotected against further drive
failure until the rebuild has finished. Therefore, replace drives during periods of low activity when
possible.
CAUTION:
If the Online LED of the replacement drive stops blinking and the amber fault LED glows, or if other
drive LEDs in the array go out, the replacement drive has failed and is producing unrecoverable disk
errors. Remove and replace the failed replacement drive.
When automatic data recovery has finished, the online LED of the replacement drive stops blinking
and begins to glow steadily.
Failure of another drive during rebuild
If a non-correctable read error occurs on another physical drive in the array during the rebuild process,
the Online LED of the replacement drive stops blinking and the rebuild abnormally terminates. If this
Troubleshooting 26