Users Guide
A dedicated hot spare can only be assigned to the set of virtual disks that share the same physical disks. A global hot spare is assigned to all redundant
virtual disks on the controller. A global hot spare must be the same size (or larger) as the smallest physical disk included in any virtual disk on the controller.
After you have assigned a global hot spare, any new virtual disks created on the controller will not be protected by the hot spare in either of the following
circumstances:
l The controller is a SCSI controller and the partition size of the disk is larger than the global hot spare.
l The controller is a SAS controller and the disk size is larger than the global hot spare.
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. See "RAID Controller Technology: SCSI, SATA, ATA, and SAS" to determine whether the controller is using SCSI or SAS technology.
On the PERC 3/SC, 3/DC, 3/QC, 4/SC, 4/DC, 4e/DC, 4/Di, 4e/Si, 4e/Di, and CERC ATA100/4ch controllers, the virtual disk state is not updated until the controller
performs an I/O operation. This means that when a redundant virtual disk is degraded on one of these controllers, the hot spare will not be activated until the
controller performs an I/O operation. See "I/O and Reboot Requirements for Detecting Physical Disk Status Changes" for more information.
Dedicated Hot Spare Considerations
The following considerations apply to dedicated hot spares:
l Considerations for RAID 10 and RAID 50. If you have created a RAID 10 or RAID 50 virtual disk that does not fully consume its member physical disks,
then you will not be able to 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 will therefore not encounter this situation if you are using 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
will not be able to assign a dedicated hot spare to the virtual disk.
l Considerations for Multiple Dedicated Hot Spares. From Storage Management version 3.1 onwards, Storage Management enables you to assign more
than one dedicated hot spare to a virtual disk.
Physical Disk State, Alert Messages and Hot Spares on PERC 3/SC, 3/DC, 3/QC, 4/SC,
4/DC, 4e/DC, 4/Di, 4e/Si, 4e/Di, and CERC ATA100/4ch Controllers
If you have a hot spare assigned to a virtual disk and a physical disk in the virtual disk fails, the failed physical disk may change from Online state to Ready
state without displaying a Failed state. This occurs when the hot spare is activated before the physical disk is able to report the Failed state. Because the
Failed state is not reported, the "Device failed: physical disk" event "2048" is not generated.
When the hot spare is activated it changes to the Rebuilding state. If you review the event log and identify a "rebuilding" event such as "2064" or "2065," you
can assume that a physical disk has failed.
Considerations for Hot Spares on PERC 3/Si, 3/Di, and CERC SATA1.5/6ch Controllers
For the PERC 3/Si, 3/Di, and CERC SATA1.5/6ch 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 not included in the virtual disk will not be rebuilt.
On the PERC 3/Si, 3/Di, and CERC SATA1.5/6ch 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 will be rebuilt. When using Storage Management, a disk that is assigned as a hot spare on a PERC 3/Si, 3/Di, and CERC
SATA1.5/6ch controller cannot also be used as a physical disk.
NOTE: This feature is applicable only on PERC 5 and PERC 6 family of controllers.
NOTE: When using the BIOS on a PERC 3/Si, 3/Di, or CERC SATA1.5/6ch controller, it may be possible to create a hot spare from a physical disk that is
also used in a virtual disk. To avoid confusion and maximize data protection, Storage Management does not allow a physical disk to be both a hot spare
and a member of a virtual disk. When assigning a hot spare, Storage Management displays the physical disks that are not being used by a virtual disk.