Hard Drive Installation and Replacement

There are several other ways to recognize that a hard drive has failed:

•The amber LED on the front of a storage system illuminates if failed drives are inside. (Other problems such as fan failure, redundant power supply failure, or over-temperature conditions also cause this LED to light up.)

•A Power-On Self-Test (POST) message lists failed drives whenever the system is restarted, as long as the controller detects one or more good drives.

•ACU represents failed drives with a distinctive icon.

•Insight Manager can detect failed drives remotely across a network. (For more information about Insight Manager, refer to the documentation on the Management CD.)

•The Array Diagnostic Utility (ADU) lists all failed drives.

For additional information about diagnosing hard drive problems, refer to the Servers Troubleshooting Guide.

Compromised Fault Tolerance

Compromised fault tolerance commonly occurs when more physical drives have failed than the fault-tolerance method can endure. In this case, the logical volume is failed and unrecoverable disk error messages are returned to the host. Data loss is likely to occur.

An example of this situation is where one drive on an array fails while another drive in the same array is still being rebuilt. If the array has no online spare, any logical drives on the array that are configured with RAID 5 fault tolerance will fail.

Compromised fault tolerance may also be caused by non-drive problems, such as temporary power loss to a storage system or a faulty cable. In such cases, the physical drives do not need to be replaced. However, data may still have been lost, especially if the system was busy at the time that the problem occurred.

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HP Smart Array 641/642 Controller User Guide