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 (you can change the priority setting by using ACU)
•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
•For RAID 5, the number of drives in the array
Allow approximately 15 minutes per gigabyte for the rebuild process to be completed. This figure is conservative, and the actual time required is usually less.
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.
When automatic data recovery has finished, the Online/Activity LED of the replacement drive stops blinking steadily at 1 Hz and begins to either glow steadily (if the drive is inactive) or flash irregularly (if the drive is active).
CAUTION: If the Online/Activity LED on the replacement drive does not light up while the corresponding LEDs on other drives in the array are active, the rebuild process has abnormally terminated. The amber Fault LED of one or more drives might also be illuminated. Refer to "Abnormal termination of a rebuild (on page 26)" to determine what action you must take.
Abnormal termination of a rebuild
If the Online/Activity LED on the replacement drive permanently ceases to be illuminated even while other drives in the array are active, the rebuild process has abnormally terminated. The following table indicates the three possible causes of abnormal termination of a rebuild.
Observation | Cause of rebuild termination |
|
|
None of the drives in the array have | One of the drives in the array has |
an illuminated amber Fault LED. | experienced an uncorrectable read error. |
|
|
The replacement drive has an | The replacement drive has failed. |
illuminated amber Fault LED. |
|
One of the other drives in the array | The drive with the illuminated Fault LED has |
has an illuminated amber Fault LED. | now failed. |
|
|
Each of these situations requires a different remedial action.
Case 1: An uncorrectable read error has occurred.
1.Back up as much data as possible from the logical drive.
CAUTION: Do not remove the drive that has the media error. Doing so causes the logical drive to fail.
2.Restore data from backup. Writing data to the location of the unreadable sector often eliminates the error.
3.Remove and reinsert the replacement drive. This action restarts the rebuild process.
If the rebuild process still terminates abnormally:
1.Delete and recreate the logical drive.
Replacing, moving, or adding hard drives 26
