The Add Disk Unit and New Disk Pool wizards save you time by bundling several time-consuming configuration functions into one efficient process. They also take the guesswork out of disk unit configuration because they understand the capabilities of your system and only offer valid choices. For instance, the wizard does not list the option to start compression unless your server has that capability.
The Add Disk Unit wizard allows you to use an existing disk pool to add new or nonconfigured disk units. When you choose to add disk units to a protected disk pool, the wizard forces you to include the disk units in device parity protection or to add enough disk units of the same capacity to start mirrored protection. The wizard also gives you the option of balancing data across the disk pool or starting disk compression if these are permissible actions for your system configuration. You decide which options to choose so that the operation is tailored to your system.
iSeries Navigator requirements for disk management.