/SPARE=sas_id
Specifies the SAS ID of the physical disk to be added as the
Global Hot Spare disk.
This qualifier is required when specifying a Global Hot Spare
disk for a RAID 1 configuration.
You can configure one Global Hot Spare disk per controller. The
spare drive can be shared between two RAID 1 IR volume sets per
controller. The size of the disk specified as /SPARE should be
greater than or equal to the size of at least one of the physical
disks on the IR volume.