HP StorageWorks 2000 Series Reference Manual page 84

To display global spares:
Select Manage > Virtual Disk Config > Global Spare Menu > Show Global Spares.
Drives whose icons are gray with a "G" are global spares.
SMU lets you manage volumes in a variety of ways. You can:
Add a volume
Expand a volume
View volume status information
Change a volume name
Change a volume's read-ahead cache settings
Enable or disable a volume's write-back cache
Delete a volume
For information about controlling host access to volumes, see XREF.
For information about master volumes, snap-pool volumes, and snapshots, see
"Using Snapshot Services" on page 104. For information about copying volumes,
see "Using Volume-Copy Services" on page 121.
A volume is a logical subdivision of a virtual disk. Using SMU you can add,
expand, rename, delete volumes, and map them to data hosts. This type of volume
provides the storage for a file system partition you create with your operating
system or third-party tools. A dual-controller system supports a maximum of 256
volumes.
A virtual disk can have one or more volumes. Using multiple volumes lets you
create one very large virtual disk making efficient use of your disk drives. For
example, you could create one very large RAID 5 virtual disk and assign one vdisk
spare to the virtual disk. This minimizes the amount of disk space allocated to parity
and spares compared to the space required if you created five or six smaller RAID 5
virtual disks.