Users Guide
When assigning a physical disk as a global hot spare on a PERC 3/Si, 3/Di, and CERC SATA1.5/6ch controller, the physical disk should be as large or larger than
the largest physical disk on the controller.
Dedicated Hot Spare Considerations on PERC 3/Si, 3/Di, and CERC SATA1.5/6ch Controllers
You can assign the same dedicated hot spare to more than one virtual disk. In this case, the hot spare attempts to rebuild all portions of redundant virtual
disks that reside on a failed physical disk. To increase the likelihood that the hot spare is able to rebuild all virtual disks, you should do the following:
1. Create virtual disks that share the same set of physical disks.
2. Only assign dedicated hot spares to those virtual disks that share the same set of physical disks.
3. Assign a hot spare that is big enough to rebuild the largest physical disk in the virtual disk. For example, if the virtual disk is using physical disks that
are 20 MB, 30 MB, and 50 MB, then the hot spare needs to be 50 MB or larger.
After the hot spare is activated to rebuild a particular virtual disk, it is no longer available for rebuilding other virtual disks should an additional physical disk
fail. For this reason, when a hot spare is activated it is automatically unassigned from the remaining virtual disks. To maintain data protection, you will need to
add a new hot spare and assign it to the other virtual disks.
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:
l 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.
l 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.
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NOTE: The "Assign and Unassign Dedicated Hot Spare" command is not available on the CERC SATA1.5/2s controller.