HP Smart Array 6400 Series Controllers Support Guide, September 2007

To minimize the likelihood of fatal system errors, take the following precautions when removing
failed disks:
• Do not remove a degraded drive when any other disk in the array is offline (the Online LED
is off). The following exceptions apply:
• When RAID 1+0 is used, drives are mirrored in pairs. Several disks can fail
simultaneously, and they can all be replaced simultaneously without data loss as long
as no two failed disks belong to the same mirrored pair.
• When RAID ADG is used, two disks can fail simultaneously and be replaced
simultaneously without data loss.
• If an online spare has an unlit Online LED (is offline), it can still be replaced.
• Do not remove a second disk from an array until the first failed or missing disk has been
replaced and the rebuild process is complete. When the rebuild is complete, the Online LED
on the front of the disk stops blinking and glows steadily. The following exceptions apply:
• In RAID ADG configurations, any two disks in the array can be replaced simultaneously.
• In RAID 1+0 configurations, any disks that are not mirrored to other removed or failed
disks can be simultaneously replaced offline without data loss.
72 Physical Disk Installation and Replacement