User's Manual

276 Protecting Your Virtual Disk with a Hot Spare
Global Hot Spare Considerations on a SAS 6/iR
The SAS 6/iR controller enables you to assign two global hot spares. The
controller firmware remembers the hot spare assignment even after the
physical disks that you assigned as hot spares have been removed. In other
words, in the case of a disk removal, the firmware may assume that a hot spare
is present when it is not. In this case, the firmware may prevent you from
assigning a new global hot spare as the firmware assumes that a global hot
spare is already assigned.
When a physical disk fails in a redundant virtual disk, the failed disk is rebuilt
onto the hot spare. In this case, the controller firmware reassigns the slot
containing the failed disk as the hot spare. In this circumstance, a disk not
previously assigned as a global hot spare becomes a hot spare through failure
or removal.
To ensure that the controller firmware always has a healthy physical disk as a
global hot spare, do the following:
• When removing a physical disk that is assigned as a global hot spare,
unassign the hot spare before removal and reassign another physical disk as
the global hot spare.
• Immediately replace any physical disk that has failed or been removed.
This ensures that a healthy disk resides in a slot that the controller
firmware assumes is a hot spare.