Use the Array >> Defragment option to consolidate all Free Capacity on a selected array. Doing so lets you create additional logical drives from the maximum amount of free capacity. A fragmented array can result from logical drive deletion or from not using all available free capacity in a Free Capacity node during logical drive creation.
You have two logical drives, "New York" and "Dallas" of 2 GB each. You would like to create a new logical drive, "Chicago" of 2 GB in the same array. The logical drive group has 2 GB of space available, but it is split between two noncontiguous Free Capacity nodes, which cannot be organized into a single logical drive.
In order to create a new logical drive "Chicago" of 2 GB, you first must defragment the array so that the space in the two Free Capacity nodes is contiguous.
In the previous example, Array 2 contained two Free Capacity nodes of 1 GB each . A Defragment Array operation on this array results in a single Free Capacity node of 2 GB.