NEC 140He User Manual page 267

When the hard disk drives are in the disk array configuration, you can restore the state before an error using the
auto-rebuild feature that stores the data in the old hard disk drive into a new one.
The auto-rebuild feature may be enabled or disabled depending on the RAID level.
Auto-rebuild is automatically carried out when you hot-swap a failed hard disk drive with a new one (replace the disk
while the server is powered). While auto-rebuild is in progress, the DISK lamp flashes green and amber alternatively to
indicate it.
IMPORTANT:
install the hard disk drive again to restart auto-rebuild. (If the disk array monitoring utility
is installed, check the indication of the utility.)
Observe the following notes for auto-rebuild.
Do not power off the server in the period between a hard disk drive error and completion of auto-rebuild.
When you removed a hard disk drive, wait at least 90 seconds before installing the hard disk drive back again.
Do not replace another hard disk drive while rebuilding is in progress. (The DISK lamp flashes green and
amber alternatively while rebuilding the hard disk drive.)
When auto-rebuild fails, the DISK lamp lights in amber. Remove and
9-9
DISK lamps