HP StorageWorks 500 G2 Modular Smart Array - Manual (Page 81)

Troubleshooting 81
Factors to consider before replacing hard drives
• In systems that use external data storage, be sure that the server is the first
unit to be powered down and the last to be powered back up. Taking this
precaution ensures that the system does not erroneously mark the drives as
failed when the server is powered up.
• If you set the SCSI ID jumpers manually:
– Check the ID value of the removed drive to be sure that it corresponds to
the ID of the drive marked as failed.
– Set the same ID value on the replacement drive to prevent SCSI ID
conflicts.
Before replacing a degraded drive:
• Open HP SIM and inspect the Error Counter window for each physical drive
in the same array to confirm that no other drives have any errors. (For details,
refer to the HP SIM documentation on the Management CD.)
• Be sure that the array has a current, valid backup.
• Use replacement drives that have a capacity at least as great as that of the
smallest drive in the array. The controller immediately fails drives that have
insufficient capacity.
To minimize the likelihood of fatal system errors, take these precautions when
removing failed drives:
• Do not remove a degraded drive if any other drive in the array is offline (the
Online LED is off). In this situation, no other drive in the array can be
removed without data loss.
Exceptions:
– When RAID 1+0 is used, drives are mirrored in pairs. Several drives can
be in a failed condition simultaneously (and they can all be replaced
simultaneously) without data loss, as long as no two failed drives belong
to the same mirrored pair.
– When RAID ADG is used, two drives can fail simultaneously (and be
replaced simultaneously) without data loss.
– If the offline drive is a spare, the degraded drive can be replaced.