User's Manual

In this case, you can unassign the global hot spare after creating a new virtual disk and then assign a new
and larger hot spare to cover all redundant virtual disks on the controller. To determine whether the
controller is using SCSI or SAS technology, see RAID Controller Technology: SCSI, SATA, ATA, and SAS.
Dedicated Hot Spare Considerations
The following considerations apply to dedicated hot spares:
• Considerations for RAID 10, RAID 50, and RAID 60 — If you have created a RAID 10 or RAID 50 virtual
disk that does not fully consume its member physical disks, then you cannot assign a dedicated hot
spare to the RAID 10 or RAID 50 virtual disk. Storage Management does not allow you to create RAID
10 and RAID 50 virtual disks from partial physical disks. You therefore do not encounter this situation if
you use Storage Management to create your virtual disks. If, however, the RAID 10 or 50 virtual disk
was created using another application and if it does contain partial physical disks, then you can assign
a dedicated hot spare to the virtual disk.
NOTE: For PERC H700 and PERC H800 controllers, you can assign a dedicated hot spare to
RAID 10, RAID 50, and RAID 60.
• Considerations for Multiple Dedicated Hot Spares — From Storage Management version 3.1 onwards,
you can assign more than one dedicated hot spare to a virtual disk.
NOTE: This feature is applicable only on PERC 5 and PERC 6 family of controllers.
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.
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