Users Guide

• Enclosure anity settings for a global/dedicated hot spare are not automatically set when you upgrade to version 6.1.
Enclosure anity settings for a global/dedicated hot spare are not automatically set when you import a foreign virtual disk.
Considerations For Hot Spares On PERC 6/E And PERC 6/I
Controllers
On the PERC 6/E and PERC 6/I controllers, assigning a hot spare is equivalent to assigning a physical disk to replace another
physical disk if it fails. If more than one redundant virtual disk resides on the physical disk, then all redundant portions of the physical
disk are rebuilt.
NOTE: When rebuilding a physical disk delete any non-redundant virtual disks (such as RAID 0) that reside on the
physical disk before rebuilding the physical disk.
NOTE: The order of the controllers displayed on Storage Management may dier with the order of the controllers
displayed in the Human Interface (HII) and PERC Option ROM. The order of the controllers does not cause any
limitation.
When creating a virtual disk, the physical disks included in the virtual disk can vary in size. Ensure that the hot spare must be the
same size (or greater) as the smallest physical disk included in the virtual disk when assigning a hot spare to a RAID 1 or 5 virtual
disk.
When you use a PERC 6/E and PERC 6/I controller, you can assign physical disks of dierent sizes to a virtual disk. When a virtual
disk is assigned to a physical disk, any portion of the physical disk that is unused by the virtual disk becomes unusable. Therefore, the
data on the unused portion of the physical disk is not rebuilt. A redundant virtual disk is also either striped or mirrored in equal
portions across its member physical disks. The amount of data requiring a rebuild is therefore not greater than the smallest physical
disk.
A RAID 10 or 50 virtual disk may include spans that have physical disks of dierent sizes. In this case, identify the span that has a low
capacity physical disk. The hot spare should be large enough to rebuild this physical disk. For example, if one span has three physical
disks that are 60MB, 60MB and 40MB and another span has physical disks that are 60MB, 60MB, and 50MB, then the hot spare
must be 50MB or larger.
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 greater) 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 are not protected by the hot spare in
either of the following circumstances:
• 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. To determine whether the controller is using SAS technology, see RAID Controller
Technology: SATA 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.
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