User's Manual

Protecting Your Virtual Disk with a Hot Spare 275

NOTE: When using the BIOS on a 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.

Size Requirements for Global Hot Spares on CERC SATA1.5/6ch, S100,

and S300 Controllers

When assigning a physical disk as a global hot spare on a CERC

SATA1.5/6ch, S100, and S300 controllers, the physical disk should be as large

or larger than the largest physical disk on the controller.

Dedicated Hot Spare Considerations on 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:

Create virtual disks that share the same set of physical disks.

Only assign dedicated hot spares to those virtual disks that share the same

set of physical disks.

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 must add a new hot spare and assign it to the other virtual

disks.

NOTE: The Assign and Unassign Dedicated Hot Spare command is not available on

the CERC SATA1.5/2s controller.