Users Guide

Considerations For Hot Spares On PERC S100 And
PERC S300 Controllers
For the PERC S100 and PERC S300 controllers, a hot spare is assigned to a virtual disk. When a physical disk fails, only the portion of the
physical disk containing the virtual disk is rebuilt onto the hot spare. Data or space on the physical disk is not included in the virtual disk are
not rebuilt.
On the PERC S100 and PERC S300 controllers, individual physical disks may be included in more than one virtual disk. Assigning a portion
of a physical disk to a virtual disk does not preclude the remaining portion of the physical disk from being used by other virtual disks. Only
the virtual disks to which the hot spare is assigned are rebuilt. When using Storage Management, a disk that is assigned as a hot spare on
a PERC S100 and PERC S300 controller cannot be used as a member of a virtual disk.
Size Requirements For Global Hot Spares On S100 And
S300 Controllers
When assigning a physical disk as a global hot spare on a PERC S100 and PERC S300 controller, the physical disk should be equal to or
greater than the largest physical disk on the controller.
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:
• Unassign the hot spare that is assigned as a global hot spare before removing and reassigning 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.
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Protecting Your Virtual Disk With A Hot Spare