User`s guide

Replacing a Drive Carrier Module
007-4522-003 99
• “LUN Integrity and Drive Carrier Module Failure” on page 99
• “Replacing the Disk Drive Module” on page 100
LUN Integrity and Drive Carrier Module Failure
When a disk drive fails in a RAID 5, 3, 1, or 0+1 LUN, the amber LEDs on all disks in the
LUN (except the failed one) alternate on and off every 1.2 seconds until the fault
condition is cleared. The amber LED on the failed disk remains lit.
Note: Before replacing a drive carrier module, use the storage system software to check
the disk status.
For a RAID 5, 3, 1, or 0+1 LUN, you can replace the disk module without powering off
the array or interrupting user applications. If the array contains a hot spare on standby,
the controller automatically rebuilds the failed module on the hot spare. A hot spare is a
special LUN that acts as a global disk spare that can be accessed by any RAID 5, 3, 1, or
0+1 LUN. A hot spare is unowned until it becomes part of a LUN when one of the LUN’s
disk modules fails.
A RAID 0 array must be taken offline to be replaced if a single disk module fails. Also, if
a second disk drive fails in a RAID 5, 3, or 1 LUN, the system drive is marked offline—
regardless of whether a second hot spare is available—and the host cannot access data
from that system drive.
In these cases, the LUN’s data integrity is compromised and it becomes unowned (not
accessible by the controller). After you replace the failed disk modules (one at a time),
you must delete and then re-create the affected LUN(s). If the data on the failed disks was
backed up, restore it to the new disks.
Note: If a disk fails in a LUN and the storage system puts the hot spare into the LUN,
use the software included with the storage system to check disk module status, and
replace the failed disk as soon as possible. The replacement becomes the new hot spare;
this arrangement (drive roaming) differs from that of other RAID systems. Therefore, it
is important to keep track of the location of the hot spare.