You can improve the server performance by ensuring that the disk units
in the disk pool have equal percentages of data residing on them. The capacity
balancing function ensures that the disk units in the disk pool are balanced.
You can balance a disk pool when you use the Add Disk Unit or New Disk Pool
wizards. To customize your system with usage balancing or hierarchical storage
management (HSM) balancing, consult Backup
and Recovery 
.
You can balance the capacity of disk pools using the Add a disk unit or disk pool wizard.