HP A7143A RAID160 SA Controller Support Guide

Hard Drive Installation and Replacement
General Aspects of Disk Drive Replacement
Appendix C148
General Aspects of Disk Drive Replacement
CAUTION Sometimes, a disk drive that has previously been failed by the controller
may seem to be operational after the system is power-cycled, or (for a
hot-pluggable drive) after the drive has been removed and reinserted.
However, continued use of such marginal drives may eventually result in
data loss. Replace the marginal drive as soon as possible.
There are several other factors to remember when replacing a disk drive:
• Non-hot-pluggable drives should only be replaced while the system is
powered down.
• Hot-pluggable drives can be removed and replaced at any time,
whether the host or storage system power is on or off.
• When a hot-pluggable drive is inserted, all disk activity on the array
pauses while the new drive is spinning up (usually 20 seconds or so).
If the drive is inserted while power is on, in a fault-tolerant
configuration, data recovery onto the replacement drive begins
automatically (indicated by the blinking Online LED).
• Replacement disk drives must have a capacity no less than that of
the smallest disk drive in the array. Drives of insufficient capacity
will be failed immediately by the controller, before automatic data
recovery can begin.
CAUTION In systems using external data storage, take care that the server is the
first unit to be powered down and the last to be powered back up. Doing
this ensures that the system will not erroneously mark the drives as
failed.
The rebuild operation takes several hours, even if the system is not busy
while the rebuild is in progress. System performance and fault tolerance
are both affected until the rebuild has finished. Therefore, replace drives